Permutations II

Given a collection of numbers that might contain duplicates, return all possible unique permutations.

For example,
[1,1,2] have the following unique permutations:
[1,1,2], [1,2,1], and [2,1,1].

 

public class Solution {
    public ArrayList<ArrayList<Integer>> permuteUnique(int[] num) {
        ArrayList<ArrayList<Integer>> res = new ArrayList<ArrayList<Integer>>();
        Arrays.sort(num);
        DFS(num,0,new boolean[num.length],new ArrayList<Integer>(),res);
        return res;
    }
    public void DFS(int num[],int start,boolean [] visited,ArrayList<Integer>output,ArrayList<ArrayList<Integer>> res){
        if(num.length==start){
            ArrayList<Integer>temp = new ArrayList<Integer>(output);
            res.add(temp);
            return;
        }
        for(int i=0;i<num.length;i++){
            if(!visited[i]){
                visited[i]=true;
                output.add(num[i]);
                DFS(num,start+1,visited,output,res);
                output.remove(output.size()-1);
                visited[i] = false;
                while(i<num.length-1 && num[i]==num[i+1]){
                    i++;
                }
                
            }
        }
    }
}

 

 

 

 Arrays.sort();

continue; not break;