LeetCode – Refresh – Generate Parentheses

Nothing fancy, just use recursive.

class Solution {
public:
    void getP(vector<string> &result, string current, int left, int right) {
        if (left == 0 && right == 0) {
            result.push_back(current);
            return;
        }
        if (left > 0) {
            getP(result, current + '(', left - 1, right + 1);
        }
        if (right > 0) {
            getP(result, current + ')', left, right - 1);
        }
    }
    vector<string> generateParenthesis(int n) {
        vector<string> result;
        getP(result, "", n, 0);
        return result;
    }
};