Source code for kyu_5.valid_parentheses.valid_parentheses

#  Created by Egor Kostan.
#  GitHub: https://github.com/ikostan
#  LinkedIn: https://www.linkedin.com/in/egor-kostan/


def valid_parentheses(string: str) -> bool:
    """
    A function called that takes a string of parentheses,
    and determines if the order of the parentheses is valid.
    The function should return true if the string is valid,
    and false if it's invalid.
    :param string:
    :return:
    """

    string = clean_up_string(string)

    if string == "" or not string:
        return True

    if len(string) % 2 != 0:
        return False

    if string.count('(') != string.count(')'):
        return False

    string_list = list(s for s in string)

    while string_list:
        pair = False

        if string_list[0] == ')':
            return False

        for s in string_list[1:]:
            if string_list[0] + s == '()':
                del string_list[0]
                string_list.remove(s)
                pair = True
                break

        if not pair:
            return False

    return True


def clean_up_string(string: str) -> str:
    """
    Cleaning up string from invalid chars
    :param string:
    :return:
    """
    return ''.join(s for s in string if s == '(' or s == ')')