class Solution:
def longestValidParentheses(self, s: str) -> int:
l, r = 0, 0
longest = 0
for i in range(len(s)):
if s[i] == "(":
l += 1
else:
r += 1
if l == r:
longest = max(longest, 2 * l)
if r > l:
l = 0
r = 0
l = 0
r = 0
for i in range(len(s) - 1, -1, -1):
if s[i] == ")":
l += 1
else:
r += 1
if l == r:
longest = max(longest, 2 * l)
if r > l:
l = 0
r = 0
return longest