刷题记录 LeetCode22:括号生成

LeetCode22:括号生成

采用回溯思想

class Solution {
public:

    vector<string> res;
    void bt(int left,int right,string st){
        if(left > right){
            return;
        }
        if(left == 0 && right ==0){
            res.push_back(st);
        }
        if(left > 0){
            bt(left - 1,right,st+"(");
        }
        if(right >0){
            bt(left, right - 1,st +")");
        }

    }

    vector<string> generateParenthesis(int n) {
        bt(n,n,"");
        return res;
    }
};