LeetCode-Generate Parentheses

题目:

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:

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

 

采用递归的方式求解

 1 class Solution{

 2 public:

 3        void generate(vector<string> &res,string curr,int m,int n){

 4                if(m==0 && n==0){ //递归终止条件

 5                    res.push_back(curr);

 6                    return;

 7                }

 8                

 9                if(m!=0) generate(res,curr+"(",m-1,n);

10                

11                if(m<n && n!=0) generate(res,curr+")",m,n-1);

12        }

13        

14        vector<string> generateParenthesis(int n){

15                vector<string> res;

16                res.clear();

17                

18                if(n>0){

19                    generate(res,string(),n,n);

20                }

21                

22                return ret;

23        }

24 };