Codewars: Valid Parentheses


Description

Write a python function such  that it 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.

Examples:

"(  )" must return "True"
"((((" must return "False"
"()()()" must return "True"
"((()" must return False

Constraints

0 <= input.length <= 100

Along with opening ( and closing ) parenthesis, input may contain any valid ASCII characters. Furthermore, the input string may be empty and/or not contain any parentheses at all. Do not treat other forms of brackets as parentheses (e.g. [], {}, <>).


Code:


def valid_parentheses(string):
    valid=[]
    for s in string:
        if s=="(":
            valid.append(s)
        elif s==")":
            try:
                valid.pop()
            except:
                return False
    if len(valid)==0:
        return True
    else:
        return False



Explanation:


1.iterate each character in string

2.if s=="(" character is added to list "valid"

3.if s==")" charcter is poped which was added before

4.if character ")" is not found "False" is returned

5.if lenght of "valid" is 0 then True is returned

6.else False is returned