leetcode 32. 最长有效括号

32. 最长有效括号

class Solution {
public:
    int max(int a, int b) { return a > b ? a : b; }
    int longestValidParentheses(string s) {
        vector<int> dp(s.size(), 0);
        int max_len = 0;
        bool flag = true;
        while(flag) {
            flag = false;
            for(int ii = 0; ii < s.size(); ) {
                if(dp[ii] == 0 && s[ii] == '(' 
                && ii + 1 < s.size()
                && ii + dp[ii + 1] < s.size() && s[ii + dp[ii + 1] + 1] == ')') {
                    dp[ii] = dp[ii + 1] + 2;
                    flag = true;
                }
                while(ii + dp[ii] < s.size() && dp[ii + dp[ii]]) {
                    dp[ii] += dp[ii + dp[ii]];
                    flag = true;
                }
                max_len = max(max_len, dp[ii]);
                ii = max(ii + 1, ii + dp[ii]);
            }
        }
        return max_len;
    }
};