【字符串】面试题 08.09. 括号

 1 class Solution {
 2 
 3     vector<string> res;
 4 public:
 5     vector<string> generateParenthesis(int n) 
 6     {
 7         backtrack("",0,0,n);
 8         return res;
 9     }
10 
11     void backtrack(string temp,int left,int right,int n)
12     {
13         if(temp.length() == n*2)
14         {
15             res.push_back(temp);
16             return ;
17         }
18         if(left<n)
19         {
20             backtrack(temp+‘(‘,left+1,right,n);
21         }
22         if(right<left)
23         {
24             backtrack(temp+‘)‘,left,right+1,n);
25         }
26     }
27 };