Generate Parentheses

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:

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

 

回溯的方法，递归实现。

1 class Solution { 2 private: 3 public: 4     void generate(int left,int right,string s,vector
     
      & result) 5     { 6         if(left==0 && right==0) 7         { 8             result.push_back(s); 9         }10         if(left>0)11         {12             generate(left-1,right,s+'(',result);13         }14         if(right>0 && left
      
        generateParenthesis(int n) {20         string s="";21         vector
       
         result;22         generate(n,n,s,result);23         return result;24     }25 };