Subsets II

Leetcode 90.

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
class Solution {
    public List<List<Integer>> subsetsWithDup(int[] nums) {
      List<Integer> list = new ArrayList<>();
      List<List<Integer>> ans = new ArrayList<>();
      boolean[] visited = new boolean[nums.length];
      Arrays.sort(nums);
      for(int i = 0; i <= nums.length;i++){
         backtricking(nums,list,ans,0,i,visited);
      }
        
      return ans;  
    }
    public void backtricking(int[] nums,List<Integer> list, List<List<Integer>> ans,int start,int depth,boolean[] visited){
     //recursion stop condition
     if(list.size() == depth){
        //collect the results
        //shallow clone
        ans.add(new ArrayList<>(list));
        return;
     }
     
     //for loop for this layer
    for(int i = start; i < nums.length;i++){
     //process the nodes   
     if(i != 0 && nums[i] == nums[i-1] && !visited[i - 1])
        continue;
     if(visited[i])
        continue;
      visited[i] = true;
      list.add(nums[i]);
      //recursion  
      backtricking(nums,list,ans,i,depth,visited);
      //undo the previous operations   
      visited[i] = false;
      list.remove(list.size() - 1);
    }
        
    }
}