Longest Valid Parentheses (Leetcode 32)

Problem Link: https://leetcode.com/problems/longest-valid-parentheses/

class Solution:
    def longestValidParentheses(self, s: str) -> int:
        ans=0
        o=0
        c=0
        for i in s:
            if(i=='('):
                o+=1
            else:
                c+=1
            if(c>o):
                c=0
                o=0
            elif(o==c):
                ans=max(ans,o+c)
        o=0
        c=0
        for i in s[::-1]:
            if(i==')'):
                c+=1
            else:
                o+=1
            if(o>c):
                c=0
                o=0
            elif(o==c):
                ans=max(ans,o+c)
        return ans