32. Longest Valid Parentheses
约 1 分钟
LeetCode 每日一题：Longest Valid Parentheses
Given a string containing just the characters '(' and ')', return the length of the longest valid (well-formed) parentheses substring.
Constraints:
0 <= s.length <= 3 * 104s[i]is'(', or')'.
思路
完全没思路，冥思苦想40分钟
python
class Solution:
def longestValidParentheses(self, s: str) -> int:
stack = [-1]
ans = 0
for i, c in enumerate(s):
if c == '(':
stack.append(i)
else:
stack.pop()
if not stack:
stack.append(i)
else:
ans = max(ans, i-stack[-1])
return ans系列每日一题 →
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