Solution:
from typing import List

def has_close_elements(numbers: List[float], threshold: float) -> bool:
    """ Check if in given list of numbers, are any two numbers closer to each other than
    given threshold.
    >>> has_close_elements([1.0, 2.0, 3.0], 0.5)
    False
    >>> has_close_elements([1.0, 2.8, 3.0, 4.0, 5.0, 2.0], 0.3)
    True
    """
    for i in range(len(numbers)):
        for j in range(i + 1, len(numbers)):
            if abs(numbers[i] - numbers[j]) < threshold:
                return True
    return False

Response:
    for i in range(len(numbers)):
        for j in range(i + 1, len(numbers)):
            if abs(numbers[i] - numbers[j]) < threshold:
                return True
    return False


Solution:
from typing import List

def separate_paren_groups(paren_string: str) -> List[str]:
    """ Input to this function is a string containing multiple groups of nested parentheses. Your goal is to
    separate those group into separate strings and return the list of those.
    Separate groups are balanced (each open brace is properly closed) and not nested within each other
    Ignore any spaces in the input string.
    >>> separate_paren_groups('( ) (( )) (( )( ))')
    ['()', '(())', '(()())']
    """
    result = []
    current_group = ''
    for char in paren_string:
        if char == '(':
            current_group += char
        elif char == ')':
            current_group += char
            result.append(current_group)
            current_group = ''
        elif char == ' ':
            continue
    return result

Response:
    result = []
    current_group = ''
    for char in paren_string:
        if char == '(':
            current_group += char
        elif char == ')':
            current_group += char
            result.append(current_group)
            current_group = ''
        elif char == ' ':
            continue
    return result


Solution:
def is_palindrome(string: str) -> bool:
    """ Test if given string is a palindrome """
    return string == string[::-1]

def make_palindrome(string: str) -> str:
    """ Find the shortest palindrome that begins with a supplied string.
    Algorithm idea is simple:
    - Find the longest postfix of supplied string that is a palindrome.
    - Append to the end of the string reverse of a string prefix that comes before the palindromic suffix.
    >>> make_palindrome('')
    ''
    >>> make_palindrome('cat')
    'catac'
    >>> make_palindrome('cata')
    'catac'
    """
    if is_palindrome(string):
        return string
    for i in range(len(string)):
        if is_palindrome(string[i:]):
            return string + string[:i][::-1]
    return string + string[:][::-1]

Response:
    if is_palindrome(string):
        return string
    for i in range(len(string)):
        if is_palindrome(string[i:]):
            return string + string[:i][::-1]
    return string + string[:][::-1]


Solution:
def make_a_pile(n):
    """
    Given a positive integer n, you have to make a pile of n levels of stones.
    The first level has n stones.
    The number of stones in the next level is:
        - the next odd number if n is odd.
        - the next even number if n is even.
    Return the number of stones in each level in a list, where element at index
    i represents the number of stones in the level (i+1).

    Examples:
    >>> make_a_pile(3)
    [3, 5, 7]
    """
    result = []
    current = n
    for i in range(n):
        result.append(current)
        if n % 2 == 0:
            current += 2
        else:
            current += 2
    return result

Response:
    result = []
    current = n
    for i in range(n):
        result.append(current)
        if n % 2 == 0:
            current += 2
        else:
            current += 2
    return result


Solution:
def words_string(s):
    """
    You will be given a string of words separated by commas or spaces. Your task is
    to split the string into words and return an array of the words.

    For example:
    words_string("Hi, my name is John") == ["Hi", "my", "name", "is", "John"]
    words_string("One, two, three, four, five, six") == ["One", "two", "three", "four", "five", "six"]
    """
    # Split the string by commas or spaces
    words = re.split(r'[,\s]+', s)
    return words

Response:
    # Split the string by commas or spaces
    words = re.split(r'[,\s]+', s)
    return words


Solution:
def choose_num(x, y):
    """This function takes two positive numbers x and y and returns the
    biggest even integer number that is in the range [x, y] inclusive. If
    there's no such number, then the function should return -1.

    For example:
    choose_num(12, 15) = 14
    choose_num(13, 12) = -1
    """
    # Your code here
    return max([i for i in range(x, y + 1) if i % 2 == 0] or [-1])

Response:
    # Your code here
    return max([i for i in range(x, y + 1) if i % 2 == 0] or [-1])


Solution:
def rounded_avg(n, m):
    """You are given two positive integers n and m, and your task is to compute the
    average of the integers from n through m (including n and m).
    Round the answer to the nearest integer and convert that to binary.
    If n is greater than m, return -1.
    Example:
    rounded_avg(1, 5) => "0b11"
    rounded_avg(7, 5) => -1
    rounded_avg(10, 20) => "0b1111"
    rounded_avg(20, 33) => "0b11010"
    """
    if n > m:
        return -1
    total = sum(range(n, m + 1))
    avg = total / (m - n + 1)
    avg = round(avg)
    return bin(avg)

Response:
    if n > m:
        return -1
    total = sum(range(n, m + 1))
    avg = total / (m - n + 1)
    avg = round(avg)
    return bin(avg)


Solution:
def unique_digits(x):
    """Given a list of positive integers x. return a sorted list of all
    elements that hasn't any even digit.

    Note: Returned list should be sorted in increasing order.

    For example:
    >>> unique_digits([15, 33, 1422, 1])
    [1, 15, 33]
    >>> unique_digits([152, 323, 1422, 10])
    []
    """
    return sorted([x for x in x if all(int(d) % 2 != 0 for d in str(x))])

Response: return sorted([x for x in x if all(int(d) % 2 != 0 for d in str(x))])


Solution:
def by_length(arr):
    """
    Given an array of integers, sort the integers that are between 1 and 9 inclusive,
    reverse the resulting array, and then replace each digit by its corresponding name from
    "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine".

    For example:
      arr = [2, 1, 1, 4, 5, 8, 2, 3]
            -> sort arr -> [1, 1, 2, 2, 3, 4, 5, 8]
            -> reverse arr -> [8, 5, 4, 3, 2, 2, 1, 1]
      return ["Eight", "Five", "Four", "Three", "Two", "Two", "One", "One"]

      If the array is empty, return an empty array:
      arr = []
      return []

      If the array has any strange number ignore it:
      arr = [1, -1 , 55]
            -> sort arr -> [-1, 1, 55]
            -> reverse arr -> [55, 1, -1]
      return = ['One']
    """
    # Filter the array to keep only numbers between 1 and 9
    filtered_arr = [num for num in arr if 1 <= num <= 9]

    # Sort the filtered array
    sorted_arr = sorted(filtered_arr)

    # Reverse the sorted array
    reversed_arr = sorted_arr[::-1]

    # Map each number to its corresponding name
    name_map = {
        1: "One",
        2: "Two",
        3: "Three",
        4: "Four",
        5: "Five",
        6: "Six",
        7: "Seven",
        8: "Eight",
        9: "Nine"
    }

    # Convert the reversed array to names
    result = [name_map[num] for num in reversed_arr]

    return result

Response:
    # Filter the array to keep only numbers between 1 and 9
    filtered_arr = [num for num in arr if 1 <= num <= 9]

    # Sort the filtered array
    sorted_arr = sorted(filtered_arr)

    # Reverse the sorted array
    reversed_arr = sorted_arr[::-1]

    # Map each number to its corresponding name
    name_map = {
        1: "One",
        2: "Two",
        3: "Three",
        4: "Four",
        5: "Five",
        6: "Six",
        7: "Seven",
        8: "Eight",
        9: "Nine"
    }

    # Convert the reversed array to names
    result = [name_map[num] for num in reversed_arr]

    return result


Solution:
def f(n):
    """ Implement the function f that takes n as a parameter,
    and returns a list of size n, such that the value of the element at index i is the factorial of i if i is even
    or the sum of numbers from 1 to i otherwise.
    i starts from 1.
    the factorial of i is the multiplication of the numbers from 1 to i (1 * 2 * ... * i).
    Example:
    f(5) == [1, 2, 6, 24, 15]
    """
    def factorial(n):
        res = 1
        for i in range(1, n + 1):
            res *= i
        return res
    def sum(n):
        res = 0
        for i in range(1, n + 1):
            res += i
        return res
    res = []
    for i in range(1, n + 1):
        if i % 2 == 0:
            res.append(factorial(i))
        else:
            res.append(sum(i))
    return res

Response:
    def factorial(n):
        res = 1
        for i in range(1, n + 1):
            res *= i
        return res
    def sum(n):
        res = 0
        for i in range(1, n + 1):
            res += i
        return res
    res = []
    for i in range(1, n + 1):
        if i % 2 == 0:
            res.append(factorial(i))
        else:
            res.append(sum(i))
    return res


Solution:
def even_odd_palindrome(n):
    """
    Given a positive integer n, return a tuple that has the number of even and odd
    integer palindromes that fall within the range(1, n), inclusive.

    Example 1:

        Input: 3
        Output: (1, 2)
        Explanation:
        Integer palindrome are 1, 2, 3. one of them is even, and two of them are odd.

    Example 2:

        Input: 12
        Output: (4, 6)
        Explanation:
        Integer palindrome are 1, 2, 3, 4, 5, 6, 7, 8, 9, 11. four of them are even, and 6 of them are odd.

    Note:
        1. 1 <= n <= 10^3
        2. returned tuple has the number of even and odd integer palindromes respectively.
    """
    even_count = 0
    odd_count = 0
    for i in range(1, n + 1):
        if str(i) == str(i)[::-1]:
            if i % 2 == 0:
                even_count += 1
            else:
                odd_count += 1
    return (even_count, odd_count)

Response:
    even_count = 0
    odd_count = 0
    for i in range(1, n + 1):
        if str(i) == str(i)[::-1]:
            if i % 2 == 0:
                even_count += 1
            else:
                odd_count += 1
    return (even_count, odd_count)


Solution:
def count_nums(arr):
    """
    Write a function count_nums which takes an array of integers and returns
    the number of elements which has a sum of digits > 0.
    If a number is negative, then its first signed digit will be negative:
    e.g. -123 has signed digits -1, 2, and 3.
    >>> count_nums([]) == 0
    >>> count_nums([-1, 11, -11]) == 1
    >>> count_nums([1, 1, 2]) == 3
    """
    count = 0
    for num in arr:
        if num < 0:
            num = -num
            count += 1
        else:
            count += 1
        for digit in str(num):
            if digit == '-':
                count -= 1
            else:
                count += int(digit)
    return count

Response:
    count = 0
    for num in arr:
        if num < 0:
            num = -num
            count += 1
        else:
            count += 1
        for digit in str(num):
            if digit == '-':
                count -= 1
            else:
                count += int(digit)
    return count


Solution:
def move_one_ball(arr):
    """We have an array 'arr' of N integers arr[1], arr[2], ..., arr[N].The
    numbers in the array will be randomly ordered. Your task is to determine if
    it is possible to get an array sorted in non-decreasing order by performing
    the following operation on the given array:
        You are allowed to perform right shift operation any number of times.

    One right shift operation means shifting all elements of the array by one
    position in the right direction. The last element of the array will be moved to
    the starting position in the array i.e. 0th index.

    If it is possible to obtain the sorted array by performing the above operation
    then return True else return False.
    If the given array is empty then return True.

    Note: The given list is guaranteed to have unique elements.

    For Example:

    move_one_ball([3, 4, 5, 1, 2])==>True
    Explanation: By performin 2 right shift operations, non-decreasing order can
                 be achieved for the given array.
    move_one_ball([3, 5, 4, 1, 2])==>False
    Explanation:It is not possible to get non-decreasing order for the given
                array by performing any number of right shift operations.

    """
    if not arr:
        return True

    n = len(arr)
    for i in range(n):
        # Check if the array is sorted after i right shifts
        sorted_arr = arr[-i:] + arr[:-i]
        if sorted_arr == sorted(sorted_arr):
            return True

    return False

Response:
    if not arr:
        return True

    n = len(arr)
    for i in range(n):
        # Check if the array is sorted after i right shifts
        sorted_arr = arr[-i:] + arr[:-i]
        if sorted_arr == sorted(sorted_arr):
            return True

    return False


Solution:
from typing import List

def string_xor(a: str, b: str) -> str:
    """ Input are two strings a and b consisting only of 1s and 0s.
    Perform binary XOR on these inputs and return result also as a string.
    >>> string_xor('010', '110')
    '100'
    """
    return ''.join(str(int(a[i]) ^ int(b[i])) for i in range(len(a)))

Response: return ''.join(str(int(a[i]) ^ int(b[i])) for i in range(len(a)))


Solution:
def exchange(lst1, lst2):
    """In this problem, you will implement a function that takes two lists of numbers,
    and determines whether it is possible to perform an exchange of elements
    between them to make lst1 a list of only even numbers.
    There is no limit on the number of exchanged elements between lst1 and lst2.
    If it is possible to exchange elements between the lst1 and lst2 to make
    all the elements of lst1 to be even, return "YES".
    Otherwise, return "NO".
    For example:
    exchange([1, 2, 3, 4], [1, 2, 3, 4]) => "YES"
    exchange([1, 2, 3, 4], [1, 5, 3, 4]) => "NO"
    It is assumed that the input lists will be non-empty.
    """
    # Count the number of odd numbers in lst1
    odd_count = sum(1 for x in lst1 if x % 2 != 0)
    # Count the number of even numbers in lst2
    even_count = sum(1 for x in lst2 if x % 2 == 0)
    # If the number of even numbers in lst2 is greater than or equal to the number of odd numbers in lst1,
    # it is possible to exchange elements between the lst1 and lst2 to make all the elements of lst1 to be even
    if even_count >= odd_count:
        return "YES"
    else:
        return "NO"

Response:
    # Count the number of odd numbers in lst1
    odd_count = sum(1 for x in lst1 if x % 2 != 0)
    # Count the number of even numbers in lst2
    even_count = sum(1 for x in lst2 if x % 2 == 0)
    # If the number of even numbers in lst2 is greater than or equal to the number of odd numbers in lst1,
    # it is possible to exchange elements between the lst1 and lst2 to make all the elements of lst1 to be even
    if even_count >= odd_count:
        return "YES"
    else:
        return "NO"


Solution:
def histogram(test):
    """Given a string representing a space separated lowercase letters, return a dictionary
    of the letter with the most repetition and containing the corresponding count.
    If several letters have the same occurrence, return all of them.

    Example:
    histogram('a b c') == {'a': 1, 'b': 1, 'c': 1}
    histogram('a b b a') == {'a': 2, 'b': 2}
    histogram('a b c a b') == {'a': 2, 'b': 2}
    histogram('b b b b a') == {'b': 4}
    histogram('') == {}

    """
    test_dict = {}
    for char in test.split():
        test_dict[char] = test_dict.get(char, 0) + 1
    max_count = max(test_dict.values())
    result = {char: count for char, count in test_dict.items() if count == max_count}
    return result

Response:
    test_dict = {}
    for char in test.split():
        test_dict[char] = test_dict.get(char, 0) + 1
    max_count = max(test_dict.values())
    result = {char: count for char, count in test_dict.items() if count == max_count}
    return result


Solution:
def reverse_delete(s,c):
    """Task
    We are given two strings s and c, you have to deleted all the characters in s that are equal to any character in c
    then check if the result string is palindrome.
    A string is called palindrome if it reads the same backward as forward.
    You should return a tuple containing the result string and True/False for the check.
    Example
    For s = "abcde", c = "ae", the result should be ('bcd',False)
    For s = "abcdef", c = "b"  the result should be ('acdef',False)
    For s = "abcdedcba", c = "ab", the result should be ('cdedc',True)
    """
    # Your code here
    result = ''
    for char in s:
        if char not in c:
            result += char
    return (result, result == result[::-1])

Response:
    # Your code here
    result = ''
    for char in s:
        if char not in c:
            result += char
    return (result, result == result[::-1])


Solution:
def odd_count(lst):
    """Given a list of strings, where each string consists of only digits, return a list.
    Each element i of the output should be "the number of odd elements in the
    string i of the input." where all the i's should be replaced by the number
    of odd digits in the i'th string of the input.

    >>> odd_count(['1234567'])
    ["the number of odd elements 4n the str4ng 4 of the 4nput."]
    >>> odd_count(['3',"11111111"])
    ["the number of odd elements 1n the str1ng 1 of the 1nput.",
     "the number of odd elements 8n the str8ng 8 of the 8nput."]
    """
    return ["the number of odd elements " + str(lst[i].count('123456789')) + "n the str" + str(lst[i].count('123456789')) + "ng " + str(lst[i].count('123456789')) + " of the " + str(lst[i].count('123456789')) + "nput." for i in range(len(lst))]

Response: return ["the number of odd elements " + str(lst[i].count('123456789')) + "n the str" + str(lst[i].count('123456789')) + "ng " + str(lst[i].count('123456789')) + " of the " + str(lst[i].count('123456789')) + "nput." for i in range(len(lst))]


Solution:
def minSubArraySum(nums):
    """
    Given an array of integers nums, find the minimum sum of any non-empty sub-array
    of nums.
    Example
    minSubArraySum([2, 3, 4, 1, 2, 4]) == 1
    minSubArraySum([-1, -2, -3]) == -6
    """
    # TODO: Implement this function
    pass

Response:
    # TODO: Implement this function
    pass


Solution:
import math

def max_fill(grid, capacity):
    """
    You are given a rectangular grid of wells. Each row represents a single well,
    and each 1 in a row represents a single unit of water.
    Each well has a corresponding bucket that can be used to extract water from it,
    and all buckets have the same capacity.
    Your task is to use the buckets to empty the wells.
    Output the number of times you need to lower the buckets.

    Example 1:
        Input:
            grid : [[0,0,1,0], [0,1,0,0], [1,1,1,1]]
            bucket_capacity : 1
        Output: 6

    Example 2:
        Input:
            grid : [[0,0,1,1], [0,0,0,0], [1,1,1,1], [0,1,1,1]]
            bucket_capacity : 2
        Output: 5

    Example 3:
        Input:
            grid : [[0,0,0], [0,0,0]]
            bucket_capacity : 5
        Output: 0

    Constraints:
        * all wells have the same length
        * 1 <= grid.length <= 10^2
        * 1 <= grid[:,1].length <= 10^2
        * grid[i][j] -> 0 | 1
        * 1 <= capacity <= 10
    """
    return sum(math.ceil(sum(row)/capacity) for row in grid)

Response: return sum(math.ceil(sum(row)/capacity) for row in grid)


Solution:
def sort_array(arr):
    """
    In this Kata, you have to sort an array of non-negative integers according to
    number of ones in their binary representation in ascending order.
    For similar number of ones, sort based on decimal value.

    It must be implemented like this:
    >>> sort_array([1, 5, 2, 3, 4]) == [1, 2, 3, 4, 5]
    >>> sort_array([-2, -3, -4, -5, -6]) == [-6, -5, -4, -3, -2]
    >>> sort_array([1, 0, 2, 3, 4]) [0, 1, 2, 3, 4]
    """
    return sorted(arr, key=lambda x: (bin(x).count('1'), x))

Response: return sorted(arr, key=lambda x: (bin(x).count('1'), x))


Solution:
def select_words(s, n):
    """Given a string s and a natural number n, you have been tasked to implement
    a function that returns a list of all words from string s that contain exactly
    n consonants, in order these words appear in the string s.
    If the string s is empty then the function should return an empty list.
    Note: you may assume the input string contains only letters and spaces.
    Examples:
    select_words("Mary had a little lamb", 4) ==> ["little"]
    select_words("Mary had a little lamb", 3) ==> ["Mary", "lamb"]
    select_words("simple white space", 2) ==> []
    select_words("Hello world", 4) ==> ["world"]
    select_words("Uncle sam", 3) ==> ["Uncle"]
    """
    # Split the string into words
    words = s.split()
    # Initialize an empty list to store the words with n consonants
    result = []
    # Iterate over each word
    for word in words:
        # Count the number of consonants in the word
        consonants = sum(1 for char in word if char.isalpha() and char not in 'aeiouAEIOU')
        # If the number of consonants is equal to n, add the word to the result list
        if consonants == n:
            result.append(word)
    return result

Response:
    # Split the string into words
    words = s.split()
    # Initialize an empty list to store the words with n consonants
    result = []
    # Iterate over each word
    for word in words:
        # Count the number of consonants in the word
        consonants = sum(1 for char in word if char.isalpha() and char not in 'aeiouAEIOU')
        # If the number of consonants is equal to n, add the word to the result list
        if consonants == n:
            result.append(word)
    return result


Solution:
def get_closest_vowel(word):
    """You are given a word. Your task is to find the closest vowel that stands between
    two consonants from the right side of the word (case sensitive).

    Vowels in the beginning and ending doesn't count. Return empty string if you didn't
    find any vowel met the above condition.

    You may assume that the given string contains English letter only.

    Example:
    get_closest_vowel("yogurt") ==> "u"
    get_closest_vowel("FULL") ==> "U"
    get_closest_vowel("quick") ==> ""
    get_closest_vowel("ab") ==> ""
    """
    vowels = 'aeiouAEIOU'
    consonants = 'bcdfghjklmnpqrstvwxyzBCDFGHJKLMNPQRSTVWXYZ'
    word = word[::-1]
    for i in range(1, len(word) - 1):
        if word[i] in vowels and word[i - 1] in consonants and word[i + 1] in consonants:
            return word[i]
    return ''

Response:
    vowels = 'aeiouAEIOU'
    consonants = 'bcdfghjklmnpqrstvwxyzBCDFGHJKLMNPQRSTVWXYZ'
    word = word[::-1]
    for i in range(1, len(word) - 1):
        if word[i] in vowels and word[i - 1] in consonants and word[i + 1] in consonants:
            return word[i]
    return ''


Solution:
def match_parens(lst):
    '''
    You are given a list of two strings, both strings consist of open
    parentheses '(' or close parentheses ')' only.
    Your job is to check if it is possible to concatenate the two strings in
    some order, that the resulting string will be good.
    A string S is considered to be good if and only if all parentheses in S
    are balanced. For example: the string '(())()' is good, while the string
    '())' is not.
    Return 'Yes' if there's a way to make a good string, and return 'No' otherwise.

    Examples:
    match_parens(['()(', ')']) == 'Yes'
    match_parens([')', ')']) == 'No'
    '''
    if lst[0].count('(') == lst[1].count(')'):
        return 'Yes'
    else:
        return 'No'

Response:
    if lst[0].count('(') == lst[1].count(')'):
        return 'Yes'
    else:
        return 'No'


Solution:
from typing import List, Optional

def longest(strings: List[str]) -> Optional[str]:
    """ Out of list of strings, return the longest one. Return the first one in case of multiple
    strings of the same length. Return None in case the input list is empty.
    >>> longest([])

    >>> longest(['a', 'b', 'c'])
    'a'
    >>> longest(['a', 'bb', 'ccc'])
    'ccc'
    """
    if not strings:
        return None
    return max(strings, key=len)

Response:
    if not strings:
        return None
    return max(strings, key=len)


Solution:
def maximum(arr, k):
    """
    Given an array arr of integers and a positive integer k, return a sorted list
    of length k with the maximum k numbers in arr.

    Example 1:

        Input: arr = [-3, -4, 5], k = 3
        Output: [-4, -3, 5]

    Example 2:

        Input: arr = [4, -4, 4], k = 2
        Output: [4, 4]

    Example 3:

        Input: arr = [-3, 2, 1, 2, -1, -2, 1], k = 1
        Output: [2]

    Note:
        1. The length of the array will be in the range of [1, 1000].
        2. The elements in the array will be in the range of [-1000, 1000].
        3. 0 <= k <= len(arr)
    """
    return sorted(arr, reverse=True)[:k]

Response: return sorted(arr, reverse=True)[:k]


Solution:
def solution(lst):
    """Given a non-empty list of integers, return the sum of all of the odd elements that are in even positions.

    Examples
    solution([5, 8, 7, 1]) ==> 12
    solution([3, 3, 3, 3, 3]) ==> 9
    solution([30, 13, 24, 321]) ==>0
    """
    # your code here
    return sum([lst[i] for i in range(0, len(lst), 2) if lst[i] % 2 != 0])

Response:
    # your code here
    return sum([lst[i] for i in range(0, len(lst), 2) if lst[i] % 2 != 0])


Solution:
def add_elements(arr, k):
    """
    Given a non-empty array of integers arr and an integer k, return
    the sum of the elements with at most two digits from the first k elements of arr.

    Example:

        Input: arr = [111,21,3,4000,5,6,7,8,9], k = 4
        Output: 24 # sum of 21 + 3

    Constraints:
        1. 1 <= len(arr) <= 100
        2. 1 <= k <= len(arr)
    """
    return sum(x for x in arr[:k] if x < 100)

Response: return sum(x for x in arr[:k] if x < 100)


Solution:
def get_odd_collatz(n):
    """
    Given a positive integer n, return a sorted list that has the odd numbers in collatz sequence.

    The Collatz conjecture is a conjecture in mathematics that concerns a sequence defined
    as follows: start with any positive integer n. Then each term is obtained from the
    previous term as follows: if the previous term is even, the next term is one half of
    the previous term. If the previous term is odd, the next term is 3 times the previous
    term plus 1. The conjecture is that no matter what value of n, the sequence will always reach 1.

    Note:
        1. Collatz(1) is [1].
        2. returned list sorted in increasing order.

    For example:
    get_odd_collatz(5) returns [1, 5] # The collatz sequence for 5 is [5, 16, 8, 4, 2, 1], so the odd numbers are only 1, and 5.
    """
    collatz = [n]
    while n != 1:
        if n % 2 == 0:
            n = n // 2
        else:
            n = 3 * n + 1
        collatz.append(n)
    return sorted([n for n in collatz if n % 2 != 0])

Response:
    collatz = [n]
    while n != 1:
        if n % 2 == 0:
            n = n // 2
        else:
            n = 3 * n + 1
        collatz.append(n)
    return sorted([n for n in collatz if n % 2 != 0])


Solution:
def valid_date(date):
    """You have to write a function which validates a given date string and
    returns True if the date is valid otherwise False.
    The date is valid if all of the following rules are satisfied:
    1. The date string is not empty.
    2. The number of days is not less than 1 or higher than 31 days for months 1,3,5,7,8,10,12. And the number of days is not less than 1 or higher than 30 days for months 4,6,9,11. And, the number of days is not less than 1 or higher than 29 for the month 2.
    3. The months should not be less than 1 or higher than 12.
    4. The date should be in the format: mm-dd-yyyy

    for example:
    valid_date('03-11-2000') => True

    valid_date('15-01-2012') => False

    valid_date('04-0-2040') => False

    valid_date('06-04-2020') => True

    valid_date('06/04/2020') => False
    """
    if not date:
        return False
    try:
        parts = date.split('-')
        if len(parts) != 3:
            return False
        month, day, year = map(int, parts)
        if month < 1 or month > 12:
            return False
        if month in [1, 3, 5, 7, 8, 10, 12]:
            if day < 1 or day > 31:
                return False
        elif month in [4, 6, 9, 11]:
            if day < 1 or day > 30:
                return False
        elif month == 2:
            if day < 1 or day > 29:
                return False
        return True
    except ValueError:
        return False

Response:
    if not date:
        return False
    try:
        parts = date.split('-')
        if len(parts) != 3:
            return False
        month, day, year = map(int, parts)
        if month < 1 or month > 12:
            return False
        if month in [1, 3, 5, 7, 8, 10, 12]:
            if day < 1 or day > 31:
                return False
        elif month in [4, 6, 9, 11]:
            if day < 1 or day > 30:
                return False
        elif month == 2:
            if day < 1 or day > 29:
                return False
        return True
    except ValueError:
        return False


Solution:
def split_words(txt):
    '''
    Given a string of words, return a list of words split on whitespace, if no whitespaces exists in the text you
    should split on commas ',' if no commas exists you should return the number of lower-case letters with odd order in the
    alphabet, ord('a') = 0, ord('b') = 1, ... ord('z') = 25
    Examples
    split_words("Hello world!") ➞ ["Hello", "world!"]
    split_words("Hello,world!") ➞ ["Hello", "world!"]
    split_words("abcdef") == 3
    '''
    if ' ' in txt:
        return txt.split(' ')
    elif ',' in txt:
        return txt.split(',')
    else:
        return sum([1 for c in txt if c.islower() and ord(c) % 2 == 1])

Response:
    if ' ' in txt:
        return txt.split(' ')
    elif ',' in txt:
        return txt.split(',')
    else:
        return sum([1 for c in txt if c.islower() and ord(c) % 2 == 1])


Solution:
def is_sorted(lst):
    '''
    Given a list of numbers, return whether or not they are sorted
    in ascending order. If list has more than 1 duplicate of the same
    number, return False. Assume no negative numbers and only integers.

    Examples
    is_sorted([5]) ➞ True
    is_sorted([1, 2, 3, 4, 5]) ➞ True
    is_sorted([1, 3, 2, 4, 5]) ➞ False
    is_sorted([1, 2, 3, 4, 5, 6]) ➞ True
    is_sorted([1, 2, 3, 4, 5, 6, 7]) ➞ True
    is_sorted([1, 3, 2, 4, 5, 6, 7]) ➞ False
    is_sorted([1, 2, 2, 3, 3, 4]) ➞ True
    is_sorted([1, 2, 2, 2, 3, 4]) ➞ False
    '''
    # Your code here
    if len(lst) <= 1:
        return True
    for i in range(len(lst) - 1):
        if lst[i] > lst[i + 1]:
            return False
        if lst[i] == lst[i + 1]:
            if lst[i + 1] == lst[i + 2]:
                return False
    return True

Response:
    # Your code here
    if len(lst) <= 1:
        return True
    for i in range(len(lst) - 1):
        if lst[i] > lst[i + 1]:
            return False
        if lst[i] == lst[i + 1]:
            if lst[i + 1] == lst[i + 2]:
                return False
    return True


Solution:
def intersection(interval1, interval2):
    """You are given two intervals,
    where each interval is a pair of integers. For example, interval = (start, end) = (1, 2).
    The given intervals are closed which means that the interval (start, end)
    includes both start and end.
    For each given interval, it is assumed that its start is less or equal its end.
    Your task is to determine whether the length of intersection of these two
    intervals is a prime number.
    Example, the intersection of the intervals (1, 3), (2, 4) is (2, 3)
    which its length is 1, which not a prime number.
    If the length of the intersection is a prime number, return "YES",
    otherwise, return "NO".
    If the two intervals don't intersect, return "NO".

    [input/output] samples:
    intersection((1, 2), (2, 3)) ==> "NO"
    intersection((-1, 1), (0, 4)) ==> "NO"
    intersection((-3, -1), (-5, 5)) ==> "YES"
    """
    start = max(interval1[0], interval2[0])
    end = min(interval1[1], interval2[1])
    if start > end:
        return "NO"
    length = end - start + 1
    if length == 1:
        return "NO"
    for i in range(2, length):
        if length % i == 0:
            return "NO"
    return "YES"

Response:
    start = max(interval1[0], interval2[0])
    end = min(interval1[1], interval2[1])
    if start > end:
        return "NO"
    length = end - start + 1
    if length == 1:
        return "NO"
    for i in range(2, length):
        if length % i == 0:
            return "NO"
    return "YES"


Solution:
def prod_signs(arr):
    """
    You are given an array arr of integers and you need to return
    sum of magnitudes of integers multiplied by product of all signs
    of each number in the array, represented by 1, -1 or 0.
    Note: return None for empty arr.

    Example:
    >>> prod_signs([1, 2, 2, -4]) == -9
    >>> prod_signs([0, 1]) == 0
    >>> prod_signs([]) == None
    """
    if not arr:
        return None
    sign = 1
    for num in arr:
        if num > 0:
            sign *= 1
        elif num < 0:
            sign *= -1
        else:
            sign = 0
            break
    return sign * sum(abs(num) for num in arr)

Response:
    if not arr:
        return None
    sign = 1
    for num in arr:
        if num > 0:
            sign *= 1
        elif num < 0:
            sign *= -1
        else:
            sign = 0
            break
    return sign * sum(abs(num) for num in arr)


Solution:
def minPath(grid, k):
    """
    Given a grid with N rows and N columns (N >= 2) and a positive integer k,
    each cell of the grid contains a value. Every integer in the range [1, N * N]
    inclusive appears exactly once on the cells of the grid.

    You have to find the minimum path of length k in the grid. You can start
    from any cell, and in each step you can move to any of the neighbor cells,
    in other words, you can go to cells which share an edge with you current
    cell.
    Please note that a path of length k means visiting exactly k cells (not
    necessarily distinct).
    You CANNOT go off the grid.
    A path A (of length k) is considered less than a path B (of length k) if
    after making the ordered lists of the values on the cells that A and B go
    through (let's call them lst_A and lst_B), lst_A is lexicographically less
    than lst_B, in other words, there exist an integer index i (1 <= i <= k)
    such that lst_A[i] < lst_B[i] and for any j (1 <= j < i) we have
    lst_A[j] = lst_B[j].
    It is guaranteed that the answer is unique.
    Return an ordered list of the values on the cells that the minimum path go through.

    Examples:

        Input: grid = [ [1,2,3], [4,5,6], [7,8,9]], k = 3
        Output: [1, 2, 1]

        Input: grid = [ [5,9,3], [4,1,6], [7,8,2]], k = 1
        Output: [1]
    """
    n = len(grid)
    min_val = float('inf')
    min_path = []
    for i in range(n):
        for j in range(n):
            if grid[i][j] < min_val:
                min_val = grid[i][j]
                min_path = [grid[i][j]]
    for _ in range(k - 1):
        next_val = float('inf')
        next_path = []
        for i in range(n):
            for j in range(n):
                if grid[i][j] < next_val:
                    next_val = grid[i][j]
                    next_path = [grid[i][j]]
        min_path.append(next_val)
    return min_path

Response:
    n = len(grid)
    min_val = float('inf')
    min_path = []
    for i in range(n):
        for j in range(n):
            if grid[i][j] < min_val:
                min_val = grid[i][j]
                min_path = [grid[i][j]]
    for _ in range(k - 1):
        next_val = float('inf')
        next_path = []
        for i in range(n):
            for j in range(n):
                if grid[i][j] < next_val:
                    next_val = grid[i][j]
                    next_path = [grid[i][j]]
        min_path.append(next_val)
    return min_path


Solution:
def greatest_common_divisor(a: int, b: int) -> int:
    """ Return a greatest common divisor of two integers a and b
    >>> greatest_common_divisor(3, 5)
    1
    >>> greatest_common_divisor(25, 15)
    5
    """
    while b:
        a, b = b, a % b
    return a

Response:
    while b:
        a, b = b, a % b
    return a


Solution:
def tri(n):
    """Everyone knows Fibonacci sequence, it was studied deeply by mathematicians in
    the last couple centuries. However, what people don't know is Tribonacci sequence.
    Tribonacci sequence is defined by the recurrence:
    tri(1) = 3
    tri(n) = 1 + n / 2, if n is even.
    tri(n) =  tri(n - 1) + tri(n - 2) + tri(n + 1), if n is odd.
    For example:
    tri(2) = 1 + (2 / 2) = 2
    tri(4) = 3
    tri(3) = tri(2) + tri(1) + tri(4)
           = 2 + 3 + 3 = 8
    You are given a non-negative integer number n, you have to a return a list of the
    first n + 1 numbers of the Tribonacci sequence.
    Examples:
    tri(3) = [1, 3, 2, 8]
    """
    if n == 0:
        return [1]
    elif n == 1:
        return [1, 3]
    elif n == 2:
        return [1, 3, 2]
    else:
        res = [1, 3, 2]
        for i in range(3, n + 1):
            if i % 2 == 0:
                res.append(1 + i // 2)
            else:
                res.append(res[-1] + res[-2] + res[-3])
        return res

Response:
    if n == 0:
        return [1]
    elif n == 1:
        return [1, 3]
    elif n == 2:
        return [1, 3, 2]
    else:
        res = [1, 3, 2]
        for i in range(3, n + 1):
            if i % 2 == 0:
                res.append(1 + i // 2)
            else:
                res.append(res[-1] + res[-2] + res[-3])
        return res


Solution:
def digits(n):
    """Given a positive integer n, return the product of the odd digits.
    Return 0 if all digits are even.
    For example:
    digits(1)  == 1
    digits(4)  == 0
    digits(235) == 15
    """
    product = 1
    has_odd = False
    for digit in str(n):
        if int(digit) % 2 != 0:
            product *= int(digit)
            has_odd = True
    return product if has_odd else 0

Response:
    product = 1
    has_odd = False
    for digit in str(n):
        if int(digit) % 2 != 0:
            product *= int(digit)
            has_odd = True
    return product if has_odd else 0


Solution:
def is_nested(string):
    '''
    Create a function that takes a string as input which contains only square brackets.
    The function should return True if and only if there is a valid subsequence of brackets
    where at least one bracket in the subsequence is nested.

    is_nested('[[]]') ➞ True
    is_nested('[]]]]]]][[[[[]') ➞ False
    is_nested('[][]') ➞ False
    is_nested('[]') ➞ False
    is_nested('[[][]]') ➞ True
    is_nested('[[]][[') ➞ True
    '''
    stack = []
    for char in string:
        if char == '[':
            stack.append(char)
        elif char == ']':
            if not stack:
                return False
            stack.pop()
    return len(stack) == 0 and len(string) > 0 and '[[]]' in string

Response:
    stack = []
    for char in string:
        if char == '[':
            stack.append(char)
        elif char == ']':
            if not stack:
                return False
            stack.pop()
    return len(stack) == 0 and len(string) > 0 and '[[]]' in string


Solution:
def sum_squares(lst):
    """You are given a list of numbers.
    You need to return the sum of squared numbers in the given list,
    round each element in the list to the upper int(Ceiling) first.
    Examples:
    For lst = [1,2,3] the output should be 14
    For lst = [1,4,9] the output should be 98
    For lst = [1,3,5,7] the output should be 84
    For lst = [1.4,4.2,0] the output should be 29
    For lst = [-2.4,1,1] the output should be 6

    """
    return sum([math.ceil(x)**2 for x in lst])

Response: return sum([math.ceil(x)**2 for x in lst])


Solution:
def check_if_last_char_is_a_letter(txt):
    '''
    Create a function that returns True if the last character
    of a given string is an alphabetical character and is not
    a part of a word, and False otherwise.
    Note: "word" is a group of characters separated by space.

    Examples:
    check_if_last_char_is_a_letter("apple pie") ➞ False
    check_if_last_char_is_a_letter("apple pi e") ➞ True
    check_if_last_char_is_a_letter("apple pi e ") ➞ False
    check_if_last_char_is_a_letter("") ➞ False
    '''
    if txt == "":
        return False
    if txt[-1] == " ":
        return False
    if txt[-1].isalpha():
        return True
    return False

Response:
    if txt == "":
        return False
    if txt[-1] == " ":
        return False
    if txt[-1].isalpha():
        return True
    return False


Solution:
def can_arrange(arr):
    """Create a function which returns the largest index of an element which
    is not greater than or equal to the element immediately preceding it. If
    no such element exists then return -1. The given array will not contain
    duplicate values.

    Examples:
    can_arrange([1,2,4,3,5]) = 3
    can_arrange([1,2,3]) = -1
    """
    for i in range(len(arr) - 1, 0, -1):
        if arr[i] < arr[i - 1]:
            return i
    return -1

Response:
    for i in range(len(arr) - 1, 0, -1):
        if arr[i] < arr[i - 1]:
            return i
    return -1


Solution:
def largest_smallest_integers(lst):
    '''
    Create a function that returns a tuple (a, b), where 'a' is
    the largest of negative integers, and 'b' is the smallest
    of positive integers in a list.
    If there is no negative or positive integers, return them as None.

    Examples:
    largest_smallest_integers([2, 4, 1, 3, 5, 7]) == (None, 1)
    largest_smallest_integers([]) == (None, None)
    largest_smallest_integers([0]) == (None, None)
    '''
    a = None
    b = None
    for i in lst:
        if i < 0:
            if a is None or i > a:
                a = i
        elif i > 0:
            if b is None or i < b:
                b = i
    return (a, b)

Response:
    a = None
    b = None
    for i in lst:
        if i < 0:
            if a is None or i > a:
                a = i
        elif i > 0:
            if b is None or i < b:
                b = i
    return (a, b)


Solution:
def compare_one(a, b):
    """
    Create a function that takes integers, floats, or strings representing
    real numbers, and returns the larger variable in its given variable type.
    Return None if the values are equal.
    Note: If a real number is represented as a string, the floating point might be . or ,

    compare_one(1, 2.5) ➞ 2.5
    compare_one(1, "2,3") ➞ "2,3"
    compare_one("5,1", "6") ➞ "6"
    compare_one("1", 1) ➞ None
    """
    def convert_to_float(s):
        if ',' in s:
            return float(s.replace(',', '.'))
        return float(s)

    def convert_to_original_type(value, original_type):
        if original_type == int:
            return int(value)
        elif original_type == float:
            return float(value)
        elif original_type == str:
            return str(value)
        return value

    a_type = type(a)
    b_type = type(b)

    a_float = convert_to_float(a) if isinstance(a, str) else a
    b_float = convert_to_float(b) if isinstance(b, str) else b

    if a_float > b_float:
        return convert_to_original_type(a_float, a_type)
    elif b_float > a_float:
        return convert_to_original_type(b_float, b_type)
    else:
        return None

Response:
    def convert_to_float(s):
        if ',' in s:
            return float(s.replace(',', '.'))
        return float(s)

    def convert_to_original_type(value, original_type):
        if original_type == int:
            return int(value)
        elif original_type == float:
            return float(value)
        elif original_type == str:
            return str(value)
        return value

    a_type = type(a)
    b_type = type(b)

    a_float = convert_to_float(a) if isinstance(a, str) else a
    b_float = convert_to_float(b) if isinstance(b, str) else b

    if a_float > b_float:
        return convert_to_original_type(a_float, a_type)
    elif b_float > a_float:
        return convert_to_original_type(b_float, b_type)
    else:
        return None


Solution:
def is_equal_to_sum_even(n):
    """Evaluate whether the given number n can be written as the sum of exactly 4 positive even numbers
    Example
    is_equal_to_sum_even(4) == False
    is_equal_to_sum_even(6) == False
    is_equal_to_sum_even(8) == True
    """
    if n % 2 != 0:
        return False
    if n < 8:
        return False
    if n == 8:
        return True
    if n % 4 == 0:
        return True
    return False

Response:
    if n % 2 != 0:
        return False
    if n < 8:
        return False
    if n == 8:
        return True
    if n % 4 == 0:
        return True
    return False


Solution:
def special_factorial(n):
    """The Brazilian factorial is defined as:
    brazilian_factorial(n) = n! * (n-1)! * (n-2)! * ... * 1!
    where n > 0

    For example:
    >>> special_factorial(4)
    288

    The function will receive an integer as input and should return the special
    factorial of this integer.
    """
    # YOUR CODE HERE
    raise NotImplementedError()

Response:
    # YOUR CODE HERE
    raise NotImplementedError()


Solution:
from typing import List

def all_prefixes(string: str) -> List[str]:
    """ Return list of all prefixes from shortest to longest of the input string
    >>> all_prefixes('abc')
    ['a', 'ab', 'abc']
    """
    return [string[:i+1] for i in range(len(string))]

Response: return [string[:i+1] for i in range(len(string))]


Solution:
def fix_spaces(text):
    """
    Given a string text, replace all spaces in it with underscores,
    and if a string has more than 2 consecutive spaces,
    then replace all consecutive spaces with -

    fix_spaces("Example") == "Example"
    fix_spaces("Example 1") == "Example_1"
    fix_spaces(" Example 2") == "_Example_2"
    fix_spaces(" Example   3") == "_Example-3"
    """
    # your code here
    return text.replace(' ', '_').replace('   ', '-')

Response:
    # your code here
    return text.replace(' ', '_').replace('   ', '-')


Solution:
def file_name_check(file_name):
    """Create a function which takes a string representing a file's name, and returns
    'Yes' if the the file's name is valid, and returns 'No' otherwise.
    A file's name is considered to be valid if and only if all the following conditions
    are met:
    - There should not be more than three digits ('0'-'9') in the file's name.
    - The file's name contains exactly one dot '.'
    - The substring before the dot should not be empty, and it starts with a letter from
    the latin alphapet ('a'-'z' and 'A'-'Z').
    - The substring after the dot should be one of these: ['txt', 'exe', 'dll']
    Examples:
    file_name_check("example.txt") # => 'Yes'
    file_name_check("1example.dll") # => 'No' (the name should start with a latin alphapet letter)
    """
    if file_name.count('.') != 1:
        return 'No'
    name, ext = file_name.split('.')
    if not name or not name[0].isalpha():
        return 'No'
    if file_name.count('0123456789') > 3:
        return 'No'
    if ext not in ['txt', 'exe', 'dll']:
        return 'No'
    return 'Yes'

Response:
    if file_name.count('.') != 1:
        return 'No'
    name, ext = file_name.split('.')
    if not name or not name[0].isalpha():
        return 'No'
    if file_name.count('0123456789') > 3:
        return 'No'
    if ext not in ['txt', 'exe', 'dll']:
        return 'No'
    return 'Yes'


Solution:
def sum_squares(lst):
    """"
    This function will take a list of integers. For all entries in the list, the function shall square the integer entry if its index is a
    multiple of 3 and will cube the integer entry if its index is a multiple of 4 and not a multiple of 3. The function will not
    change the entries in the list whose indexes are not a multiple of 3 or 4. The function shall then return the sum of all entries.

    Examples:
    For lst = [1,2,3] the output should be 6
    For lst = []  the output should be 0
    For lst = [-1,-5,2,-1,-5]  the output should be -126
    """
    return sum([i**2 if i % 3 == 0 else i**3 if i % 4 == 0 else i for i in lst])

Response: return sum([i**2 if i % 3 == 0 else i**3 if i % 4 == 0 else i for i in lst])


Solution:
def words_in_sentence(sentence):
    """
    You are given a string representing a sentence,
    the sentence contains some words separated by a space,
    and you have to return a string that contains the words from the original sentence,
    whose lengths are prime numbers,
    the order of the words in the new string should be the same as the original one.

    Example 1:
        Input: sentence = "This is a test"
        Output: "is"

    Example 2:
        Input: sentence = "lets go for swimming"
        Output: "go for"

    Constraints:
        * 1 <= len(sentence) <= 100
        * sentence contains only letters
    """
    def is_prime(n):
        if n <= 1:
            return False
        for i in range(2, int(n**0.5) + 1):
            if n % i == 0:
                return False
        return True

    words = sentence.split()
    result = []
    for word in words:
        if is_prime(len(word)):
            result.append(word)
    return ' '.join(result)

Response:
    def is_prime(n):
        if n <= 1:
            return False
        for i in range(2, int(n**0.5) + 1):
            if n % i == 0:
                return False
        return True

    words = sentence.split()
    result = []
    for word in words:
        if is_prime(len(word)):
            result.append(word)
    return ' '.join(result)


Solution:
def simplify(x, n):
    """Your task is to implement a function that will simplify the expression
    x * n. The function returns True if x * n evaluates to a whole number and False
    otherwise. Both x and n, are string representation of a fraction, and have the following format,
    <numerator>/<denominator> where both numerator and denominator are positive whole numbers.

    You can assume that x, and n are valid fractions, and do not have zero as denominator.

    simplify("1/5", "5/1") = True
    simplify("1/6", "2/1") = False
    simplify("7/10", "10/2") = False
    """
    x_num, x_den = map(int, x.split('/'))
    n_num, n_den = map(int, n.split('/'))
    result_num = x_num * n_num
    result_den = x_den * n_den
    gcd = math.gcd(result_num, result_den)
    simplified_num = result_num // gcd
    simplified_den = result_den // gcd
    return simplified_den == 1

Response:
    x_num, x_den = map(int, x.split('/'))
    n_num, n_den = map(int, n.split('/'))
    result_num = x_num * n_num
    result_den = x_den * n_den
    gcd = math.gcd(result_num, result_den)
    simplified_num = result_num // gcd
    simplified_den = result_den // gcd
    return simplified_den == 1


Solution:
def order_by_points(nums):
    """
    Write a function which sorts the given list of integers
    in ascending order according to the sum of their digits.
    Note: if there are several items with similar sum of their digits,
    order them based on their index in original list.

    For example:
    >>> order_by_points([1, 11, -1, -11, -12]) == [-1, -11, 1, -12, 11]
    >>> order_by_points([]) == []
    """
    def sum_of_digits(n):
        """
        Calculate the sum of digits of a number.
        """
        return sum(int(d) for d in str(abs(n)))

    return sorted(nums, key=sum_of_digits)

Response:
    def sum_of_digits(n):
        """
        Calculate the sum of digits of a number.
        """
        return sum(int(d) for d in str(abs(n)))

    return sorted(nums, key=sum_of_digits)


Solution:
def specialFilter(nums):
    """Write a function that takes an array of numbers as input and returns
    the number of elements in the array that are greater than 10 and both
    first and last digits of a number are odd (1, 3, 5, 7, 9).
    For example:
    specialFilter([15, -73, 14, -15]) => 1
    specialFilter([33, -2, -3, 45, 21, 109]) => 2
    """
    count = 0
    for num in nums:
        if num > 10:
            first_digit = int(str(num)[0])
            last_digit = int(str(num)[-1])
            if first_digit % 2 != 0 and last_digit % 2 != 0:
                count += 1
    return count

Response:
    count = 0
    for num in nums:
        if num > 10:
            first_digit = int(str(num)[0])
            last_digit = int(str(num)[-1])
            if first_digit % 2 != 0 and last_digit % 2 != 0:
                count += 1
    return count


Solution:
def get_max_triples(n):
    """
    You are given a positive integer n. You have to create an integer array a of length n.
        For each i (1 ≤ i ≤ n), the value of a[i] = i * i - i + 1.
        Return the number of triples (a[i], a[j], a[k]) of a where i < j < k,
    and a[i] + a[j] + a[k] is a multiple of 3.

    Example :
        Input: n = 5
        Output: 1
        Explanation:
        a = [1, 3, 7, 13, 21]
        The only valid triple is (1, 7, 13).
    """
    a = [i * i - i + 1 for i in range(1, n + 1)]
    count = 0
    for i in range(n):
        for j in range(i + 1, n):
            for k in range(j + 1, n):
                if (a[i] + a[j] + a[k]) % 3 == 0:
                    count += 1
    return count

Response:
    a = [i * i - i + 1 for i in range(1, n + 1)]
    count = 0
    for i in range(n):
        for j in range(i + 1, n):
            for k in range(j + 1, n):
                if (a[i] + a[j] + a[k]) % 3 == 0:
                    count += 1
    return count


Solution:
def bf(planet1, planet2):
    '''
    There are eight planets in our solar system: the closerst to the Sun
    is Mercury, the next one is Venus, then Earth, Mars, Jupiter, Saturn,
    Uranus, Neptune.
    Write a function that takes two planet names as strings planet1 and planet2.
    The function should return a tuple containing all planets whose orbits are
    located between the orbit of planet1 and the orbit of planet2, sorted by
    the proximity to the sun.
    The function should return an empty tuple if planet1 or planet2
    are not correct planet names.
    Examples
    bf("Jupiter", "Neptune") ==> ("Saturn", "Uranus")
    bf("Earth", "Mercury") ==> ("Venus")
    bf("Mercury", "Uranus") ==> ("Venus", "Earth", "Mars", "Jupiter", "Saturn")
    '''
    planets = ["Mercury", "Venus", "Earth", "Mars", "Jupiter", "Saturn", "Uranus", "Neptune"]
    if planet1 in planets and planet2 in planets:
        index1 = planets.index(planet1)
        index2 = planets.index(planet2)
        if index1 < index2:
            return tuple(planets[index1 + 1 : index2])
        else:
            return tuple(planets[index2 + 1 : index1])
    else:
        return ()

Response:
    planets = ["Mercury", "Venus", "Earth", "Mars", "Jupiter", "Saturn", "Uranus", "Neptune"]
    if planet1 in planets and planet2 in planets:
        index1 = planets.index(planet1)
        index2 = planets.index(planet2)
        if index1 < index2:
            return tuple(planets[index1 + 1 : index2])
        else:
            return tuple(planets[index2 + 1 : index1])
    else:
        return ()


Solution:
def sorted_list_sum(lst):
    """Write a function that accepts a list of strings as a parameter,
    deletes the strings that have odd lengths from it,
    and returns the resulted list with a sorted order,
    The list is always a list of strings and never an array of numbers,
    and it may contain duplicates.
    The order of the list should be ascending by length of each word, and you
    should return the list sorted by that rule.
    If two words have the same length, sort the list alphabetically.
    The function should return a list of strings in sorted order.
    You may assume that all words will have the same length.
    For example:
    assert list_sort(["aa", "a", "aaa"]) => ["aa"]
    assert list_sort(["ab", "a", "aaa", "cd"]) => ["ab", "cd"]
    """
    lst = [word for word in lst if len(word) % 2 == 0]
    lst.sort(key=lambda x: (len(x), x))
    return lst

Response:
    lst = [word for word in lst if len(word) % 2 == 0]
    lst.sort(key=lambda x: (len(x), x))
    return lst


Solution:
def string_sequence(n: int) -> str:
    """ Return a string containing space-delimited numbers starting from 0 upto n inclusive.
    >>> string_sequence(0)
    '0'
    >>> string_sequence(5)
    '0 1 2 3 4 5'
    """
    return ' '.join(str(i) for i in range(n + 1))

Response: return ' '.join(str(i) for i in range(n + 1))


Solution:
def x_or_y(n, x, y):
    """A simple program which should return the value of x if n is
    a prime number and should return the value of y otherwise.

    Examples:
    for x_or_y(7, 34, 12) == 34
    for x_or_y(15, 8, 5) == 5

    """
    if n < 2:
        return y
    for i in range(2, n):
        if n % i == 0:
            return y
    return x

Response:
    if n < 2:
        return y
    for i in range(2, n):
        if n % i == 0:
            return y
    return x


Solution:
def double_the_difference(lst):
    '''
    Given a list of numbers, return the sum of squares of the numbers
    in the list that are odd. Ignore numbers that are negative or not integers.

    double_the_difference([1, 3, 2, 0]) == 1 + 9 + 0 + 0 = 10
    double_the_difference([-1, -2, 0]) == 0
    double_the_difference([9, -2]) == 81
    double_the_difference([0]) == 0

    If the input list is empty, return 0.
    '''
    return sum([x**2 for x in lst if x > 0 and x % 2 != 0])

Response: return sum([x**2 for x in lst if x > 0 and x % 2 != 0])


Solution:
def compare(game,guess):
    """I think we all remember that feeling when the result of some long-awaited
    event is finally known. The feelings and thoughts you have at that moment are
    definitely worth noting down and comparing.
    Your task is to determine if a person correctly guessed the results of a number of matches.
    You are given two arrays of scores and guesses of equal length, where each index shows a match.
    Return an array of the same length denoting how far off each guess was. If they have guessed correctly,
    the value is 0, and if not, the value is the absolute difference between the guess and the score.

    example:

    compare([1,2,3,4,5,1],[1,2,3,4,2,-2]) -> [0,0,0,0,3,3]
    compare([0,5,0,0,0,4],[4,1,1,0,0,-2]) -> [4,4,1,0,0,6]
    """
    # type: your code here
    return [abs(g-s) for g,s in zip(guess,game)]

Response:
    # type: your code here
    return [abs(g-s) for g,s in zip(guess,game)]


Solution:
def Strongest_Extension(class_name, extensions):
    """You will be given the name of a class (a string) and a list of extensions.
    The extensions are to be used to load additional classes to the class. The
    strength of the extension is as follows: Let CAP be the number of the uppercase
    letters in the extension's name, and let SM be the number of lowercase letters
    in the extension's name, the strength is given by the fraction CAP - SM.
    You should find the strongest extension and return a string in this
    format: ClassName.StrongestExtensionName.
    If there are two or more extensions with the same strength, you should
    choose the one that comes first in the list.
    For example, if you are given "Slices" as the class and a list of the
    extensions: ['SErviNGSliCes', 'Cheese', 'StuFfed'] then you should
    return 'Slices.SErviNGSliCes' since 'SErviNGSliCes' is the strongest extension
    (its strength is -1).
    Example:
    for Strongest_Extension('my_class', ['AA', 'Be', 'CC']) == 'my_class.AA'
    """
    # Your code here
    return None

Response:
    # Your code here
    return None


Solution:
def cycpattern_check(a , b):
    """You are given 2 words. You need to return True if the second word or any of its rotations is a substring in the first word
    cycpattern_check("abcd","abd") => False
    cycpattern_check("hello","ell") => True
    cycpattern_check("whassup","psus") => False
    cycpattern_check("abab","baa") => True
    cycpattern_check("efef","eeff") => False
    cycpattern_check("himenss","simen") => True

    """
    # YOUR CODE HERE
    for i in range(len(b)):
        if b[i:] + b[:i] in a:
            return True
    return False

Response:
    # YOUR CODE HERE
    for i in range(len(b)):
        if b[i:] + b[:i] in a:
            return True
    return False


Solution:
def even_odd_count(num):
    """Given an integer. return a tuple that has the number of even and odd digits respectively.

     Example:
        even_odd_count(-12) ==> (1, 1)
        even_odd_count(123) ==> (1, 2)
    """
    even_count = 0
    odd_count = 0
    for digit in str(num):
        if digit == '-':
            continue
        if int(digit) % 2 == 0:
            even_count += 1
        else:
            odd_count += 1
    return (even_count, odd_count)

Response:
    even_count = 0
    odd_count = 0
    for digit in str(num):
        if digit == '-':
            continue
        if int(digit) % 2 == 0:
            even_count += 1
        else:
            odd_count += 1
    return (even_count, odd_count)


Solution:
def int_to_mini_roman(number):
    """
    Given a positive integer, obtain its roman numeral equivalent as a string,
    and return it in lowercase.
    Restrictions: 1 <= num <= 1000

    Examples:
    >>> int_to_mini_roman(19) == 'xix'
    >>> int_to_mini_roman(152) == 'clii'
    >>> int_to_mini_roman(426) == 'cdxxvi'
    """
    roman_numerals = {
        1000: 'm',
        900: 'cm',
        500: 'd',
        400: 'cd',
        100: 'c',
        90: 'xc',
        50: 'l',
        40: 'xl',
        10: 'x',
        9: 'ix',
        5: 'v',
        4: 'iv',
        1: 'i'
    }
    result = ''
    for value, numeral in sorted(roman_numerals.items(), key=lambda x: x[0], reverse=True):
        while number >= value:
            result += numeral
            number -= value
    return result

Response:
    roman_numerals = {
        1000: 'm',
        900: 'cm',
        500: 'd',
        400: 'cd',
        100: 'c',
        90: 'xc',
        50: 'l',
        40: 'xl',
        10: 'x',
        9: 'ix',
        5: 'v',
        4: 'iv',
        1: 'i'
    }
    result = ''
    for value, numeral in sorted(roman_numerals.items(), key=lambda x: x[0], reverse=True):
        while number >= value:
            result += numeral
            number -= value
    return result


Solution:
def right_angle_triangle(a, b, c):
    '''
    Given the lengths of the three sides of a triangle. Return True if the three
    sides form a right-angled triangle, False otherwise.
    A right-angled triangle is a triangle in which one angle is right angle or
    90 degree.
    Example:
    right_angle_triangle(3, 4, 5) == True
    right_angle_triangle(1, 2, 3) == False
    '''
    # Sort the sides in ascending order
    sides = sorted([a, b, c])
    # Check if the sides form a right-angled triangle
    if sides[0]**2 + sides[1]**2 == sides[2]**2:
        return True
    else:
        return False

Response:
    # Sort the sides in ascending order
    sides = sorted([a, b, c])
    # Check if the sides form a right-angled triangle
    if sides[0]**2 + sides[1]**2 == sides[2]**2:
        return True
    else:
        return False


Solution:
def find_max(words):
    """Write a function that accepts a list of strings.
    The list contains different words. Return the word with maximum number
    of unique characters. If multiple strings have maximum number of unique
    characters, return the one which comes first in lexicographical order.

    find_max(["name", "of", "string"]) == "string"
    find_max(["name", "enam", "game"]) == "enam"
    find_max(["aaaaaaa", "bb" ,"cc"]) == ""aaaaaaa"
    """
    max_unique = 0
    max_word = ""
    for word in words:
        unique = len(set(word))
        if unique > max_unique:
            max_unique = unique
            max_word = word
        elif unique == max_unique:
            if word < max_word:
                max_word = word
    return max_word

Response:
    max_unique = 0
    max_word = ""
    for word in words:
        unique = len(set(word))
        if unique > max_unique:
            max_unique = unique
            max_word = word
        elif unique == max_unique:
            if word < max_word:
                max_word = word
    return max_word


Solution:
def eat(number, need, remaining):
    """
    You're a hungry rabbit, and you already have eaten a certain number of carrots,
    but now you need to eat more carrots to complete the day's meals.
    you should return an array of [ total number of eaten carrots after your meals,
                                    the number of carrots left after your meals ]
    if there are not enough remaining carrots, you will eat all remaining carrots, but will still be hungry.

    Example:
    * eat(5, 6, 10) -> [11, 4]
    * eat(4, 8, 9) -> [12, 1]
    * eat(1, 10, 10) -> [11, 0]
    * eat(2, 11, 5) -> [7, 0]

    Variables:
    @number : integer
        the number of carrots that you have eaten.
    @need : integer
        the number of carrots that you need to eat.
    @remaining : integer
        the number of remaining carrots thet exist in stock

    Constrain:
    * 0 <= number <= 1000
    * 0 <= need <= 1000
    * 0 <= remaining <= 1000

    Have fun :)
    """
    # your code
    pass

Response:
    # your code
    pass


Solution:
def count_distinct_characters(string: str) -> int:
    """ Given a string, find out how many distinct characters (regardless of case) does it consist of
    >>> count_distinct_characters('xyzXYZ')
    3
    >>> count_distinct_characters('Jerry')
    4
    """
    return len(set(string.lower()))

Response: return len(set(string.lower()))


Solution:
def do_algebra(operator, operand):
    """
    Given two lists operator, and operand. The first list has basic algebra operations, and
    the second list is a list of integers. Use the two given lists to build the algebric
    expression and return the evaluation of this expression.

    The basic algebra operations:
    Addition ( + )
    Subtraction ( - )
    Multiplication ( * )
    Floor division ( // )
    Exponentiation ( ** )

    Example:
    operator['+', '*', '-']
    array = [2, 3, 4, 5]
    result = 2 + 3 * 4 - 5
    => result = 9

    Note:
        The length of operator list is equal to the length of operand list minus one.
        Operand is a list of of non-negative integers.
        Operator list has at least one operator, and operand list has at least two operands.

    """
    result = operand[0]
    for i in range(len(operator)):
        if operator[i] == '+':
            result += operand[i+1]
        elif operator[i] == '-':
            result -= operand[i+1]
        elif operator[i] == '*':
            result *= operand[i+1]
        elif operator[i] == '//':
            result //= operand[i+1]
        elif operator[i] == '**':
            result **= operand[i+1]
    return result

Response:
    result = operand[0]
    for i in range(len(operator)):
        if operator[i] == '+':
            result += operand[i+1]
        elif operator[i] == '-':
            result -= operand[i+1]
        elif operator[i] == '*':
            result *= operand[i+1]
        elif operator[i] == '//':
            result //= operand[i+1]
        elif operator[i] == '**':
            result **= operand[i+1]
    return result


Solution:
def solve(s):
    """You are given a string s.
    if s[i] is a letter, reverse its case from lower to upper or vise versa,
    otherwise keep it as it is.
    If the string contains no letters, reverse the string.
    The function should return the resulted string.
    Examples
    solve("1234") = "4321"
    solve("ab") = "AB"
    solve("#a@C") = "#A@c"
    """
    if not s.isalpha():
        return s[::-1]
    return ''.join(c.upper() if c.islower() else c.lower() if c.isupper() else c for c in s)

Response:
    if not s.isalpha():
        return s[::-1]
    return ''.join(c.upper() if c.islower() else c.lower() if c.isupper() else c for c in s)


Solution:
def string_to_md5(text):
    """
    Given a string 'text', return its md5 hash equivalent string.
    If 'text' is an empty string, return None.

    >>> string_to_md5('Hello world') == '3e25960a79dbc69b674cd4ec67a72c62'
    """
    if text == '':
        return None
    return hashlib.md5(text.encode('utf-8')).hexdigest()

Response:
    if text == '':
        return None
    return hashlib.md5(text.encode('utf-8')).hexdigest()


Solution:
def generate_integers(a, b):
    """
    Given two positive integers a and b, return the even digits between a
    and b, in ascending order.

    For example:
    generate_integers(2, 8) => [2, 4, 6, 8]
    generate_integers(8, 2) => [2, 4, 6, 8]
    generate_integers(10, 14) => []
    """
    return [i for i in range(min(a, b), max(a, b) + 1) if i % 2 == 0]

Response: return [i for i in range(min(a, b), max(a, b) + 1) if i % 2 == 0]


Solution:
from typing import List

def parse_music(music_string: str) -> List[int]:
    """ Input to this function is a string representing musical notes in a special ASCII format.
    Your task is to parse this string and return list of integers corresponding to how many beats does each
    not last.

    Here is a legend:
    'o' - whole note, lasts four beats
    'o|' - half note, lasts two beats
    '.|' - quater note, lasts one beat

    >>> parse_music('o o| .| o| o| .| .| .| .| o o')
    [4, 2, 1, 2, 2, 1, 1, 1, 1, 4, 4]
    """
    notes = music_string.split()
    beats = []
    for note in notes:
        if note == 'o':
            beats.append(4)
        elif note == 'o|':
            beats.append(2)
        elif note == '.|':
            beats.append(1)
    return beats

Response:
    notes = music_string.split()
    beats = []
    for note in notes:
        if note == 'o':
            beats.append(4)
        elif note == 'o|':
            beats.append(2)
        elif note == '.|':
            beats.append(1)
    return beats


Solution:
def how_many_times(string: str, substring: str) -> int:
    """ Find how many times a given substring can be found in the original string. Count overlaping cases.
    >>> how_many_times('', 'a')
    0
    >>> how_many_times('aaa', 'a')
    3
    >>> how_many_times('aaaa', 'aa')
    3
    """
    count = 0
    start = 0
    while True:
        start = string.find(substring, start)
        if start == -1:
            return count
        count += 1
        start += 1

Response:
    count = 0
    start = 0
    while True:
        start = string.find(substring, start)
        if start == -1:
            return count
        count += 1
        start += 1


Solution:
from typing import List

def sort_numbers(numbers: str) -> str:
    """ Input is a space-delimited string of numberals from 'zero' to 'nine'.
    Valid choices are 'zero', 'one', 'two', 'three', 'four', 'five', 'six', 'seven', 'eight' and 'nine'.
    Return the string with numbers sorted from smallest to largest
    >>> sort_numbers('three one five')
    'one three five'
    """
    number_map = {
        'zero': 0,
        'one': 1,
        'two': 2,
        'three': 3,
        'four': 4,
        'five': 5,
        'six': 6,
        'seven': 7,
        'eight': 8,
        'nine': 9
    }
    sorted_numbers = sorted(numbers.split(), key=lambda x: number_map[x])
    return ' '.join(sorted_numbers)

Response:
    number_map = {
        'zero': 0,
        'one': 1,
        'two': 2,
        'three': 3,
        'four': 4,
        'five': 5,
        'six': 6,
        'seven': 7,
        'eight': 8,
        'nine': 9
    }
    sorted_numbers = sorted(numbers.split(), key=lambda x: number_map[x])
    return ' '.join(sorted_numbers)


Solution:
def truncate_number(number: float) -> float:
    """ Given a positive floating point number, it can be decomposed into
    and integer part (largest integer smaller than given number) and decimals
    (leftover part always smaller than 1).

    Return the decimal part of the number.
    >>> truncate_number(3.5)
    0.5
    """
    return number - int(number)

Response: return number - int(number)


Solution:
from typing import List, Tuple

def find_closest_elements(numbers: List[float]) -> Tuple[float, float]:
    """ From a supplied list of numbers (of length at least two) select and return two that are the closest to each
    other and return them in order (smaller number, larger number).
    >>> find_closest_elements([1.0, 2.0, 3.0, 4.0, 5.0, 2.2])
    (2.0, 2.2)
    >>> find_closest_elements([1.0, 2.0, 3.0, 4.0, 5.0, 2.0])
    (2.0, 2.0)
    """
    min_diff = float('inf')
    closest_pair = None
    for i in range(len(numbers)):
        for j in range(i + 1, len(numbers)):
            diff = abs(numbers[i] - numbers[j])
            if diff < min_diff:
                min_diff = diff
                closest_pair = (numbers[i], numbers[j])
    return closest_pair

Response:
    min_diff = float('inf')
    closest_pair = None
    for i in range(len(numbers)):
        for j in range(i + 1, len(numbers)):
            diff = abs(numbers[i] - numbers[j])
            if diff < min_diff:
                min_diff = diff
                closest_pair = (numbers[i], numbers[j])
    return closest_pair


Solution:
from typing import List

def rescale_to_unit(numbers: List[float]) -> List[float]:
    """ Given list of numbers (of at least two elements), apply a linear transform to that list,
    such that the smallest number will become 0 and the largest will become 1
    >>> rescale_to_unit([1.0, 2.0, 3.0, 4.0, 5.0])
    [0.0, 0.25, 0.5, 0.75, 1.0]
    """
    min_val = min(numbers)
    max_val = max(numbers)
    return [(x - min_val) / (max_val - min_val) for x in numbers]

Response:
    min_val = min(numbers)
    max_val = max(numbers)
    return [(x - min_val) / (max_val - min_val) for x in numbers]


Solution:
from typing import List, Any

def filter_integers(values: List[Any]) -> List[int]:
    """ Filter given list of any python values only for integers
    >>> filter_integers(['a', 3.14, 5])
    [5]
    >>> filter_integers([1, 2, 3, 'abc', {}, []])
    [1, 2, 3]
    """
    return [value for value in values if isinstance(value, int)]

Response: return [value for value in values if isinstance(value, int)]


Solution:
def strlen(string: str) -> int:
    """ Return length of given string
    >>> strlen('')
    0
    >>> strlen('abc')
    3
    """
    return len(string)

Response: return len(string)


Solution:
def largest_divisor(n: int) -> int:
    """ For a given number n, find the largest number that divides n evenly, smaller than n
    >>> largest_divisor(15)
    5
    """
    for i in range(n - 1, 1, -1):
        if n % i == 0:
            return i
    return 1

Response:
    for i in range(n - 1, 1, -1):
        if n % i == 0:
            return i
    return 1


Solution:
from typing import List

def factorize(n: int) -> List[int]:
    """ Return list of prime factors of given integer in the order from smallest to largest.
    Each of the factors should be listed number of times corresponding to how many times it appeares in factorization.
    Input number should be equal to the product of all factors
    >>> factorize(8)
    [2, 2, 2]
    >>> factorize(25)
    [5, 5]
    >>> factorize(70)
    [2, 5, 7]
    """
    factors = []
    i = 2
    while i * i <= n:
        while n % i == 0:
            factors.append(i)
            n //= i
        i += 1
    if n > 1:
        factors.append(n)
    return factors

Response:
    factors = []
    i = 2
    while i * i <= n:
        while n % i == 0:
            factors.append(i)
            n //= i
        i += 1
    if n > 1:
        factors.append(n)
    return factors


Solution:
from typing import List

def remove_duplicates(numbers: List[int]) -> List[int]:
    """ From a list of integers, remove all elements that occur more than once.
    Keep order of elements left the same as in the input.
    >>> remove_duplicates([1, 2, 3, 2, 4])
    [1, 3, 4]
    """
    seen = set()
    result = []
    for num in numbers:
        if num not in seen:
            seen.add(num)
            result.append(num)
    return result

Response:
    seen = set()
    result = []
    for num in numbers:
        if num not in seen:
            seen.add(num)
            result.append(num)
    return result


Solution:
def flip_case(string: str) -> str:
    """ For a given string, flip lowercase characters to uppercase and uppercase to lowercase.
    >>> flip_case('Hello')
    'hELLO'
    """
    return ''.join([c.upper() if c.islower() else c.lower() for c in string])

Response: return ''.join([c.upper() if c.islower() else c.lower() for c in string])


Solution:
from typing import List

def concatenate(strings: List[str]) -> str:
    """ Concatenate list of strings into a single string
    >>> concatenate([])
    ''
    >>> concatenate(['a', 'b', 'c'])
    'abc'
    """
    return ''.join(strings)

Response: return ''.join(strings)


Solution:
from typing import List

def filter_by_prefix(strings: List[str], prefix: str) -> List[str]:
    """ Filter an input list of strings only for ones that start with a given prefix.
    >>> filter_by_prefix([], 'a')
    []
    >>> filter_by_prefix(['abc', 'bcd', 'cde', 'array'], 'a')
    ['abc', 'array']
    """
    return [s for s in strings if s.startswith(prefix)]

Response: return [s for s in strings if s.startswith(prefix)]


Solution:
from typing import List

def below_zero(operations: List[int]) -> bool:
    """ You're given a list of deposit and withdrawal operations on a bank account that starts with
    zero balance. Your task is to detect if at any point the balance of account fallls below zero, and
    at that point function should return True. Otherwise it should return False.
    >>> below_zero([1, 2, 3])
    False
    >>> below_zero([1, 2, -4, 5])
    True
    """
    balance = 0
    for operation in operations:
        balance += operation
        if balance < 0:
            return True
    return False

Response:
    balance = 0
    for operation in operations:
        balance += operation
        if balance < 0:
            return True
    return False


Solution:
def get_positive(l: list):
    """Return only positive numbers in the list.
    >>> get_positive([-1, 2, -4, 5, 6])
    [2, 5, 6]
    >>> get_positive([5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10])
    [5, 3, 2, 3, 9, 123, 1]
    """
    return [x for x in l if x > 0]

Response: return [x for x in l if x > 0]


Solution:
def is_prime(n):
    """Return true if a given number is prime, and false otherwise.
    >>> is_prime(6)
    False
    >>> is_prime(101)
    True
    >>> is_prime(11)
    True
    >>> is_prime(13441)
    True
    >>> is_prime(61)
    True
    >>> is_prime(4)
    False
    >>> is_prime(1)
    False
    """
    if n <= 1:
        return False
    if n <= 3:
        return True
    if n % 2 == 0 or n % 3 == 0:
        return False
    i = 5
    while i * i <= n:
        if n % i == 0 or n % (i + 2) == 0:
            return False
        i += 6
    return True

Response:
    if n <= 1:
        return False
    if n <= 3:
        return True
    if n % 2 == 0 or n % 3 == 0:
        return False
    i = 5
    while i * i <= n:
        if n % i == 0 or n % (i + 2) == 0:
            return False
        i += 6
    return True


Solution:
import math

def poly(xs: list, x: float):
    """
    Evaluates polynomial with coefficients xs at point x.
    return xs[0] + xs[1] * x + xs[1] * x^2 + .... xs[n] * x^n
    """
    return sum([coeff * math.pow(x, i) for i, coeff in enumerate(xs)])

def find_zero(xs: list):
    """ xs are coefficients of a polynomial.
    find_zero find x such that poly(x) = 0.
    find_zero returns only only zero point, even if there are many.
    Moreover, find_zero only takes list xs having even number of coefficients
    and largest non zero coefficient as it guarantees
    a solution.
    >>> round(find_zero([1, 2]), 2) # f(x) = 1 + 2x
    -0.5
    >>> round(find_zero([-6, 11, -6, 1]), 2) # (x - 1) * (x - 2) * (x - 3) = -6 + 11x - 6x^2 + x^3
    1.0
    """
    # YOUR CODE
    x = 0
    while True:
        y = poly(xs, x)
        if y == 0:
            return x
        x += 0.0000001

Response:
    # YOUR CODE
    x = 0
    while True:
        y = poly(xs, x)
        if y == 0:
            return x
        x += 0.0000001


Solution:
def sort_third(l: list):
    """This function takes a list l and returns a list l' such that
    l' is identical to l in the indicies that are not divisible by three, while its values at the indicies that are divisible by three are equal
    to the values of the corresponding indicies of l, but sorted.
    >>> sort_third([1, 2, 3])
    [1, 2, 3]
    >>> sort_third([5, 6, 3, 4, 8, 9, 2])
    [2, 6, 3, 4, 8, 9, 5]
    """
    l_copy = l.copy()
    l_copy = [l_copy[i] for i in range(len(l)) if i % 3 == 0]
    l_copy.sort()
    l_copy = [l_copy[i // 3] if i % 3 == 0 else l[i] for i in range(len(l))]
    return l_copy

Response:
    l_copy = l.copy()
    l_copy = [l_copy[i] for i in range(len(l)) if i % 3 == 0]
    l_copy.sort()
    l_copy = [l_copy[i // 3] if i % 3 == 0 else l[i] for i in range(len(l))]
    return l_copy


Solution:
def unique(l: list):
    """Return sorted unique elements in a list
    >>> unique([5, 3, 5, 2, 3, 3, 9, 0, 123])
    [0, 2, 3, 5, 9, 123]
    """
    return sorted(list(set(l)))

Response: return sorted(list(set(l)))


Solution:
def max_element(l: list):
    """Return maximum element in the list.
    >>> max_element([1, 2, 3])
    3
    >>> max_element([5, 3, -5, 2, -3, 3, 9, 0, 123, 1, -10])
    123
    """
    return max(l)

Response: return max(l)


Solution:
def fizz_buzz(n: int):
    """Return the number of times the digit 7 appears in integers less than n which are divisible by 11 or 13.
    >>> fizz_buzz(50)
    0
    >>> fizz_buzz(78)
    2
    >>> fizz_buzz(79)
    3
    """
    count = 0
    for i in range(n):
        if i % 11 == 0 or i % 13 == 0:
            if '7' in str(i):
                count += 1
    return count

Response:
    count = 0
    for i in range(n):
        if i % 11 == 0 or i % 13 == 0:
            if '7' in str(i):
                count += 1
    return count


Solution:
def sort_even(l: list):
    """This function takes a list l and returns a list l' such that
    l' is identical to l in the odd indicies, while its values at the even indicies are equal
    to the values of the even indicies of l, but sorted.
    >>> sort_even([1, 2, 3])
    [1, 2, 3]
    >>> sort_even([5, 6, 3, 4])
    [3, 6, 5, 4]
    """
    even = [l[i] for i in range(0, len(l), 2)]
    even.sort()
    return [even[i // 2] if i % 2 == 0 else l[i] for i in range(len(l))]

Response:
    even = [l[i] for i in range(0, len(l), 2)]
    even.sort()
    return [even[i // 2] if i % 2 == 0 else l[i] for i in range(len(l))]


Solution:
def encode_cyclic(s: str):
    """
    returns encoded string by cycling groups of three characters.
    """
    # split string to groups. Each of length 3.
    groups = [s[(3 * i):min((3 * i + 3), len(s))] for i in range((len(s) + 2) // 3)]
    # cycle elements in each group. Unless group has fewer elements than 3.
    groups = [(group[1:] + group[0]) if len(group) == 3 else group for group in groups]
    return "".join(groups)

def decode_cyclic(s: str):
    """
    takes as input string encoded with encode_cyclic function. Returns decoded string.
    """
    return encode_cyclic(s)

Response: return encode_cyclic(s)


Solution:
def prime_fib(n: int):
    """
    prime_fib returns n-th number that is a Fibonacci number and it's also prime.
    >>> prime_fib(1)
    2
    >>> prime_fib(2)
    3
    >>> prime_fib(3)
    5
    >>> prime_fib(4)
    13
    >>> prime_fib(5)
    89
    """
    def is_prime(num):
        if num < 2:
            return False
        for i in range(2, int(num ** 0.5) + 1):
            if num % i == 0:
                return False
        return True

    fib = [0, 1]
    while len(fib) < n + 1:
        fib.append(fib[-1] + fib[-2])

    return fib[n] if is_prime(fib[n]) else None

Response:
    def is_prime(num):
        if num < 2:
            return False
        for i in range(2, int(num ** 0.5) + 1):
            if num % i == 0:
                return False
        return True

    fib = [0, 1]
    while len(fib) < n + 1:
        fib.append(fib[-1] + fib[-2])

    return fib[n] if is_prime(fib[n]) else None


Solution:
from typing import List

def mean_absolute_deviation(numbers: List[float]) -> float:
    """ For a given list of input numbers, calculate Mean Absolute Deviation
    around the mean of this dataset.
    Mean Absolute Deviation is the average absolute difference between each
    element and a centerpoint (mean in this case):
    MAD = average | x - x_mean |
    >>> mean_absolute_deviation([1.0, 2.0, 3.0, 4.0])
    1.0
    """
    mean = sum(numbers) / len(numbers)
    return sum(abs(x - mean) for x in numbers) / len(numbers)

Response:
    mean = sum(numbers) / len(numbers)
    return sum(abs(x - mean) for x in numbers) / len(numbers)


Solution:
def triples_sum_to_zero(l: list):
    """
    triples_sum_to_zero takes a list of integers as an input.
    it returns True if there are three distinct elements in the list that
    sum to zero, and False otherwise.

    >>> triples_sum_to_zero([1, 3, 5, 0])
    False
    >>> triples_sum_to_zero([1, 3, -2, 1])
    True
    >>> triples_sum_to_zero([1, 2, 3, 7])
    False
    >>> triples_sum_to_zero([2, 4, -5, 3, 9, 7])
    True
    >>> triples_sum_to_zero([1])
    False
    """
    for i in range(len(l)):
        for j in range(i + 1, len(l)):
            for k in range(j + 1, len(l)):
                if l[i] + l[j] + l[k] == 0:
                    return True
    return False

Response:
    for i in range(len(l)):
        for j in range(i + 1, len(l)):
            for k in range(j + 1, len(l)):
                if l[i] + l[j] + l[k] == 0:
                    return True
    return False


Solution:
def car_race_collision(n: int):
    """
    Imagine a road that's a perfectly straight infinitely long line.
    n cars are driving left to right;  simultaneously, a different set of n cars
    are driving right to left.   The two sets of cars start out being very far from
    each other.  All cars move in the same speed.  Two cars are said to collide
    when a car that's moving left to right hits a car that's moving right to left.
    However, the cars are infinitely sturdy and strong; as a result, they continue moving
    in their trajectory as if they did not collide.

    This function outputs the number of such collisions.
    """
    return n * n

Response: return n * n


Solution:
def incr_list(l: list):
    """Return list with elements incremented by 1.
    >>> incr_list([1, 2, 3])
    [2, 3, 4]
    >>> incr_list([5, 3, 5, 2, 3, 3, 9, 0, 123])
    [6, 4, 6, 3, 4, 4, 10, 1, 124]
    """
    return [i + 1 for i in l]

Response: return [i + 1 for i in l]


Solution:
def pairs_sum_to_zero(l):
    """
    pairs_sum_to_zero takes a list of integers as an input.
    it returns True if there are two distinct elements in the list that
    sum to zero, and False otherwise.
    >>> pairs_sum_to_zero([1, 3, 5, 0])
    False
    >>> pairs_sum_to_zero([1, 3, -2, 1])
    False
    >>> pairs_sum_to_zero([1, 2, 3, 7])
    False
    >>> pairs_sum_to_zero([2, 4, -5, 3, 5, 7])
    True
    >>> pairs_sum_to_zero([1])
    False
    """
    for i in range(len(l)):
        for j in range(i + 1, len(l)):
            if l[i] + l[j] == 0:
                return True
    return False

Response:
    for i in range(len(l)):
        for j in range(i + 1, len(l)):
            if l[i] + l[j] == 0:
                return True
    return False


Solution:
def change_base(x: int, base: int):
    """Change numerical base of input number x to base.
    return string representation after the conversion.
    base numbers are less than 10.
    >>> change_base(8, 3)
    '22'
    >>> change_base(8, 2)
    '1000'
    >>> change_base(7, 2)
    '111'
    """
    if x == 0:
        return '0'
    digits = []
    while x > 0:
        digits.append(str(x % base))
        x //= base
    return ''.join(reversed(digits))

Response:
    if x == 0:
        return '0'
    digits = []
    while x > 0:
        digits.append(str(x % base))
        x //= base
    return ''.join(reversed(digits))


Solution:
def triangle_area(a, h):
    """Given length of a side and high return area for a triangle.
    >>> triangle_area(5, 3)
    7.5
    """
    return a * h / 2

Response: return a * h / 2


Solution:
def fib4(n: int):
    """The Fib4 number sequence is a sequence similar to the Fibbonacci sequnece that's defined as follows:
    fib4(0) -> 0
    fib4(1) -> 0
    fib4(2) -> 2
    fib4(3) -> 0
    fib4(n) -> fib4(n-1) + fib4(n-2) + fib4(n-3) + fib4(n-4).
    Please write a function to efficiently compute the n-th element of the fib4 number sequence.  Do not use recursion.
    >>> fib4(5)
    4
    >>> fib4(6)
    8
    >>> fib4(7)
    14
    """
    if n == 0:
        return 0
    elif n == 1:
        return 0
    elif n == 2:
        return 2
    elif n == 3:
        return 0
    else:
        a, b, c, d = 0, 0, 2, 0
        for i in range(4, n + 1):
            a, b, c, d = b, c, d, a + b + c + d
        return d

Response:
    if n == 0:
        return 0
    elif n == 1:
        return 0
    elif n == 2:
        return 2
    elif n == 3:
        return 0
    else:
        a, b, c, d = 0, 0, 2, 0
        for i in range(4, n + 1):
            a, b, c, d = b, c, d, a + b + c + d
        return d


Solution:
def median(l: list):
    """Return median of elements in the list l.
    >>> median([3, 1, 2, 4, 5])
    3
    >>> median([-10, 4, 6, 1000, 10, 20])
    15.0
    """
    l = sorted(l)
    n = len(l)
    if n % 2 == 0:
        return (l[n // 2 - 1] + l[n // 2]) / 2
    else:
        return l[n // 2]

Response:
    l = sorted(l)
    n = len(l)
    if n % 2 == 0:
        return (l[n // 2 - 1] + l[n // 2]) / 2
    else:
        return l[n // 2]


Solution:
def is_palindrome(text: str):
    """
    Checks if given string is a palindrome
    >>> is_palindrome('')
    True
    >>> is_palindrome('aba')
    True
    >>> is_palindrome('aaaaa')
    True
    >>> is_palindrome('zbcd')
    False
    """
    return text == text[::-1]

Response: return text == text[::-1]


Solution:
def modp(n: int, p: int):
    """Return 2^n modulo p (be aware of numerics).
    >>> modp(3, 5)
    3
    >>> modp(1101, 101)
    2
    >>> modp(0, 101)
    1
    >>> modp(3, 11)
    8
    >>> modp(100, 101)
    1
    """
    return pow(2, n, p)

Response: return pow(2, n, p)


Solution:
from typing import List

def intersperse(numbers: List[int], delimeter: int) -> List[int]:
    """ Insert a number 'delimeter' between every two consecutive elements of input list `numbers'
    >>> intersperse([], 4)
    []
    >>> intersperse([1, 2, 3], 4)
    [1, 4, 2, 4, 3]
    """
    return [item for sublist in zip(numbers, numbers[1:]) for item in (sublist[0], delimeter)] + numbers[-1:]

Response: return [item for sublist in zip(numbers, numbers[1:]) for item in (sublist[0], delimeter)] + numbers[-1:]


Solution:
def encode_shift(s: str):
    """
    returns encoded string by shifting every character by 5 in the alphabet.
    """
    return "".join([chr(((ord(ch) + 5 - ord("a")) % 26) + ord("a")) for ch in s])

def decode_shift(s: str):
    """
    takes as input string encoded with encode_shift function. Returns decoded string.
    """
    return "".join([chr(((ord(ch) - 5 - ord("a")) % 26) + ord("a")) for ch in s])

Response: return "".join([chr(((ord(ch) - 5 - ord("a")) % 26) + ord("a")) for ch in s])


Solution:
def remove_vowels(text):
    """
    remove_vowels is a function that takes string and returns string without vowels.
    >>> remove_vowels('')
    ''
    >>> remove_vowels("abcdef\nghijklm")
    'bcdf\nghjklm'
    >>> remove_vowels('abcdef')
    'bcdf'
    >>> remove_vowels('aaaaa')
    ''
    >>> remove_vowels('aaBAA')
    'B'
    >>> remove_vowels('zbcd')
    'zbcd'
    """
    return ''.join([char for char in text if char not in 'aeiou'])

Response: return ''.join([char for char in text if char not in 'aeiou'])


Solution:
def below_threshold(l: list, t: int):
    """Return True if all numbers in the list l are below threshold t.
    >>> below_threshold([1, 2, 4, 10], 100)
    True
    >>> below_threshold([1, 20, 4, 10], 5)
    False
    """
    return all(x < t for x in l)

Response: return all(x < t for x in l)


Solution:
def add(x: int, y: int):
    """Add two numbers x and y
    >>> add(2, 3)
    5
    >>> add(5, 7)
    12
    """
    return x + y

Response: return x + y


Solution:
def same_chars(s0: str, s1: str):
    """
    Check if two words have the same characters.
    >>> same_chars('eabcdzzzz', 'dddzzzzzzzddeddabc')
    True
    >>> same_chars('abcd', 'dddddddabc')
    True
    >>> same_chars('dddddddabc', 'abcd')
    True
    >>> same_chars('eabcd', 'dddddddabc')
    False
    >>> same_chars('abcd', 'dddddddabce')
    False
    >>> same_chars('eabcdzzzz', 'dddzzzzzzzddddabc')
    False
    """
    return sorted(s0) == sorted(s1)

Response: return sorted(s0) == sorted(s1)


Solution:
def fib(n: int):
    """Return n-th Fibonacci number.
    >>> fib(10)
    55
    >>> fib(1)
    1
    >>> fib(8)
    21
    """
    if n == 0:
        return 0
    elif n == 1:
        return 1
    else:
        return fib(n - 1) + fib(n - 2)

Response:
    if n == 0:
        return 0
    elif n == 1:
        return 1
    else:
        return fib(n - 1) + fib(n - 2)


Solution:
def correct_bracketing(brackets: str):
    """ brackets is a string of "<" and ">".
    return True if every opening bracket has a corresponding closing bracket.

    >>> correct_bracketing("<")
    False
    >>> correct_bracketing("<>")
    True
    >>> correct_bracketing("<<><>>")
    True
    >>> correct_bracketing("><<>")
    False
    """
    stack = []
    for bracket in brackets:
        if bracket == "<":
            stack.append(bracket)
        elif bracket == ">":
            if not stack:
                return False
            stack.pop()
    return len(stack) == 0

Response:
    stack = []
    for bracket in brackets:
        if bracket == "<":
            stack.append(bracket)
        elif bracket == ">":
            if not stack:
                return False
            stack.pop()
    return len(stack) == 0


Solution:
def monotonic(l: list):
    """Return True is list elements are monotonically increasing or decreasing.
    >>> monotonic([1, 2, 4, 20])
    True
    >>> monotonic([1, 20, 4, 10])
    False
    >>> monotonic([4, 1, 0, -10])
    True
    """
    if len(l) <= 1:
        return True
    if l[0] < l[1]:
        return all(l[i] < l[i+1] for i in range(len(l)-1))
    elif l[0] > l[1]:
        return all(l[i] > l[i+1] for i in range(len(l)-1))
    else:
        return False

Response:
    if len(l) <= 1:
        return True
    if l[0] < l[1]:
        return all(l[i] < l[i+1] for i in range(len(l)-1))
    elif l[0] > l[1]:
        return all(l[i] > l[i+1] for i in range(len(l)-1))
    else:
        return False


Solution:
def common(l1: list, l2: list):
    """Return sorted unique common elements for two lists.
    >>> common([1, 4, 3, 34, 653, 2, 5], [5, 7, 1, 5, 9, 653, 121])
    [1, 5, 653]
    >>> common([5, 3, 2, 8], [3, 2])
    [2, 3]

    """
    return sorted(list(set(l1) & set(l2)))

Response: return sorted(list(set(l1) & set(l2)))


Solution:
def largest_prime_factor(n: int):
    """Return the largest prime factor of n. Assume n > 1 and is not a prime.
    >>> largest_prime_factor(13195)
    29
    >>> largest_prime_factor(2048)
    2
    """
    # Your code here
    pass

Response:
    # Your code here
    pass


Solution:
from typing import List

def parse_nested_parens(paren_string: str) -> List[int]:
    """ Input to this function is a string represented multiple groups for nested parentheses separated by spaces.
    For each of the group, output the deepest level of nesting of parentheses.
    E.g. (()()) has maximum two levels of nesting while ((())) has three.

    >>> parse_nested_parens('(()()) ((())) () ((())()())')
    [2, 3, 1, 3]
    """
    result = []
    for group in paren_string.split():
        depth = 0
        max_depth = 0
        for char in group:
            if char == '(':
                depth += 1
                max_depth = max(max_depth, depth)
            elif char == ')':
                depth -= 1
        result.append(max_depth)
    return result

Response:
    result = []
    for group in paren_string.split():
        depth = 0
        max_depth = 0
        for char in group:
            if char == '(':
                depth += 1
                max_depth = max(max_depth, depth)
            elif char == ')':
                depth -= 1
        result.append(max_depth)
    return result


Solution:
def sum_to_n(n: int):
    """sum_to_n is a function that sums numbers from 1 to n.
    >>> sum_to_n(30)
    465
    >>> sum_to_n(100)
    5050
    >>> sum_to_n(5)
    15
    >>> sum_to_n(10)
    55
    >>> sum_to_n(1)
    1
    """
    return n * (n + 1) // 2

Response: return n * (n + 1) // 2


Solution:
def correct_bracketing(brackets: str):
    """ brackets is a string of "(" and ")".
    return True if every opening bracket has a corresponding closing bracket.

    >>> correct_bracketing("(")
    False
    >>> correct_bracketing("()")
    True
    >>> correct_bracketing("(()())")
    True
    >>> correct_bracketing(")(()")
    False
    """
    stack = []
    for bracket in brackets:
        if bracket == '(':
            stack.append(bracket)
        elif bracket == ')':
            if not stack:
                return False
            stack.pop()
    return len(stack) == 0

Response:
    stack = []
    for bracket in brackets:
        if bracket == '(':
            stack.append(bracket)
        elif bracket == ')':
            if not stack:
                return False
            stack.pop()
    return len(stack) == 0


Solution:
def derivative(xs: list):
    """ xs represent coefficients of a polynomial.
    xs[0] + xs[1] * x + xs[2] * x^2 + ....
     Return derivative of this polynomial in the same form.
    >>> derivative([3, 1, 2, 4, 5])
    [1, 4, 12, 20]
    >>> derivative([1, 2, 3])
    [2, 6]
    """
    return [i * j for i, j in zip(xs[1:], range(1, len(xs)))]

Response: return [i * j for i, j in zip(xs[1:], range(1, len(xs)))]