LC 0032 [H] Longest Valid Parentheses - ALawliet/algorithms GitHub Wiki

class Solution:
    def longestValidParentheses(self, s: str) -> int:
        stack = [-1]
        
        longest = 0
        
        for i in range(len(s)):
            top = stack[-1]
            
            if len(stack) > 1 and s[top] == '(' and s[i] == ')':
                stack.pop()
                newTop = stack[-1]
                longest = max(i - newTop, longest)
            else:
                stack.append(i)
                
        return longest

class Solution:
    def longestValidParentheses(self, s: str) -> int:
        stack = [-1]
        
        r = 0
        
        for i in range(len(s)):
            if s[i] == '(':
                stack.append(i)
            else:
                stack.pop()
                if not stack:
                    stack.append(i)
                else:
                    r = max(r, i - stack[-1])
                    
        return r