Codility Lesson 7 Nesting Python

Question

A string S consisting of N characters is called properly nested if:

S is empty;
S has the form "(U)" where U is a properly nested string;
S has the form "VW" where V and W are properly nested strings.
For example, string "(()(())())" is properly nested but string "())" isn't.

Write a function:

def solution(S)

that, given a string S consisting of N characters, returns 1 if string S is properly nested and 0 otherwise.

For example, given S = "(()(())())", the function should return 1 and given S = "())", the function should return 0, as explained above.

Write an efficient algorithm for the following assumptions:

N is an integer within the range [0..1,000,000];
string S is made only of the characters '(' and/or ')'.

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Answer

def solution(S):
    queue = []
    for s in S:
        if s == '(':
            queue.append(s)
        else:
            if len(queue) == 0:
                return 0
            else:
                queue.pop()
    if len(queue) > 0:
        return 0
    return 1