LeetCode-22.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:

[
  "((()))",
  "(()())",
  "(())()",
  "()(())",
  "()()()"
]

使用DFS+剪枝

 1 class Solution {//DFS 剪枝 mytip
 2     public List<String> generateParenthesis(int n) {
 3         List<String> re = new ArrayList<>();
 4         generate(n,n,re,"");
 5         return re;
 6         
 7     }
 8     private void generate(int left,int right,List<String> re ,String s){
 9         if(0==left&&0==right){
10             re.add(s);
11             return;
12         }
13         if(left>0){
14             generate(left-1,right,re,s+"(");
15         }
16         if(left<right){
17             generate(left,right-1,re,s+")");
18         }
19     }
20 }

LeetCode-22.Generate Parentheses

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