代码语言:javascript复制
class Solution {
public:
int longestValidParentheses(string s) {
int res = 0, start = 0;
stack<int> m;
for (int i = 0; i < s.size(); i) {
if (s[i] == '(') m.push(i);
else if (s[i] == ')') {
if (m.empty()) start = i 1;
else {
m.pop();
res = m.empty() ? max(res, i - start 1) : max(res, i - m.top());
}
}
}
return res;
}
};