leetcode------Subsets II

标题：	Subsets II
通过率：	27.5
难度：	中等

Given a collection of integers that might contain duplicates, 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 = [1,2,2], a solution is:

[

  [2],

  [1],

  [1,2,2],

  [2,2],

  [1,2],

  []

]

从第一个版本中可以看出来，这里需要增加相同判断。具体看代码

 1 public class Solution {

 2     public ArrayList<ArrayList<Integer>> subsetsWithDup(int[] num) {

 3         ArrayList<ArrayList<Integer>> res=new ArrayList<ArrayList<Integer>>();

 4         ArrayList<Integer> tmp=new ArrayList<Integer>();

 5         Arrays.sort(num);

 6         dfs(res,tmp,0,num);

 7         return res;

 8     }

 9     public void dfs(ArrayList<ArrayList<Integer>> res,ArrayList<Integer> tmp,int start,int[] num){

10         if(!res.contains(tmp))

11             res.add(new ArrayList<Integer>(tmp));

12         for(int i=start;i<num.length;i++){

13             tmp.add(num[i]);

14             dfs(res,tmp,i+1,num);

15             tmp.remove(tmp.size()-1);

16         }

17     }

18 }