Leetcode-Permutations II

 1 public class Solution {
 2     public List<List<Integer>> permuteUnique(int[] num) {
 3         boolean[] used = new boolean[num.length];
 4         Arrays.fill(used,false);
 5         Arrays.sort(num);
 6         List<List<Integer>> resSet = new ArrayList<List<Integer>>();
 7         List<Integer> curStr = new ArrayList<Integer>();
 8         permuteRecur(num,used,0,curStr,resSet);
 9         return resSet;        
10     }
11 
12     public void permuteRecur(int[] num, boolean[] used, int cur, List<Integer> curStr, List<List<Integer>> resSet){
13         if (cur==num.length){
14             List<Integer> res = new ArrayList<Integer>();
15             res.addAll(curStr);
16             resSet.add(res);
17             return;
18         }
19 
20         boolean init = true;
21         int lastVal = -1;
22         for (int i=0;i<num.length;i++)
23             if (used[i] || (!init && num[i]==lastVal))
24                 continue;
25             else {
26                 init = false;
27                 curStr.add(num[i]);
28                 used[i]=true;
29                 permuteRecur(num,used,cur+1,curStr,resSet);
30                 used[i]=false;
31                 curStr.remove(curStr.size()-1);
32                 lastVal = num[i];
33             }
34     }
35 }