22. Generate Parentheses

22. Generate Parentheses

Total Accepted: 70039 Total Submissions: 203043 Difficulty: Medium

Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses.

For example, given n = 3, a solution set is:

"((()))", "(()())", "(())()", "()(())", "()()()"

Hide Tags

 Backtracking String

Hide Similar Problems

 (M) Letter Combinations of a Phone Number (E) Valid Parentheses

 

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

Next challenges: (H) Sudoku Solver (H) Longest Substring with At Most Two Distinct Characters (E) Group Shifted Strings