LeetCode – Refresh – Longest Valid Parentheses

Notes:

Do not forget to clean the total and rec.

class Solution {
public:
    int longestValidParentheses(string s) {
        int len = s.size(), total = 0, rec = 0, result = 0;
        for (int i = 0; i < len; i++) {
            if (s[i] == '(') {
                total++;
                rec++;
            } else {
                total++;
                rec--;
            }
            if (rec < 0) {
                total = 0;
                rec = 0;
            } else if (rec == 0) {
                result = max(result, total);
            }
        }
        total = 0, rec = 0;
        for (int i = len-1; i >= 0; i--) {
            if (s[i] == ')') {
                total++;
                rec++;
            } else {
                total++;
                rec--;
            }
            if (rec < 0) {
                total = 0;
                rec = 0;
            } else if (rec == 0) {
                result = max(result, total);
            }
        }
        return result;
    }
};