Subsets

Given a set of distinct integers, S, return all possible subsets.

Note:

  • Elements in a subset must be in non-descending order.
  • The solution set must not contain duplicate subsets.

 

For example,
If S = [1,2,3], a solution is:

[
  [3],
  [1],
  [2],
  [1,2,3],
  [1,3],
  [2,3],
  [1,2],
  []
]
 1 public class Solution {
 2     public ArrayList<ArrayList<Integer>> subsets(int[] S) {
 3        ArrayList<ArrayList<Integer>> res = new ArrayList<ArrayList<Integer>>();
 4        ArrayList<Integer> output = new ArrayList<Integer>();
 5        Arrays.sort(S);
 6        res.add(new ArrayList<Integer>());
 7        DFS(S,0,output,res);
 8        return res;
 9     }
10     
11     public void DFS(int[] S,int start, ArrayList<Integer>output,ArrayList<ArrayList<Integer>>res){
12         for(int i=start;i<S.length;i++){
13             output.add(S[i]);
14             ArrayList<Integer> temp = new ArrayList<Integer>();
15             temp.addAll(output);
16             res.add(temp);
17             DFS(S,i+1,output,res);
18             output.remove(output.size()-1);
19         }
20     }
21 }
View Code

 

 
posted @ 2014-02-06 14:50  krunning  阅读(140)  评论(0)  编辑  收藏  举报