[LeetCode]Subsets II

[LeetCode]Subsets II

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],
    []
  ]

  遞歸+增量構造法

  public class Solution {
  	List> res = new ArrayList>();
  	List list = new ArrayList();
      public List> subsetsWithDup(int[] num) {
      	Arrays.sort(num);
          help(num,0);
          return res;
      }
  
      private  void help(int[]num,int start){
      	if(!res.contains(list)){
      		List lin = new ArrayList(list);
      	    res.add(lin);
      	}
      	for(int i=start;i