Longest paren substring

2022-08-15.py

question = """
Given a string s consisting of various parenthesis ( and ), 
find the length of the longest valid parenthesis substring.

Example:

> parensSubstring('(()(')
> 2

> parensSubstring(')()(()))')
> 6

"""

import re

def parensSubstring(string):
    length = 0
    p = re.compile(r'\(\)')
    m = p.search(string)
    while m:
        length += 2
        string = re.sub(r'\(\)', '', string, 1)
        m = p.search(string)
    return length

print(parensSubstring('(()('))
print(parensSubstring(')()(()))'))