【LeetCode OJ 090】Subsets II淺析

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

   

  [
    [2],
    [1],
    [1,2,2],
    [2,2],
    [1,2],
    []
  ]

  解題思路：這題與第78題相似，不同之處在於這題給定的數組中重復的數字，參照78題思路，再利用HashSet就可以過濾掉重復的list，具體實現見下面代碼：

   

   

  public class Solution
  {
  	public List> subsetsWithDup(int[] nums) 
  	{
  		List> result=new ArrayList>();
  		HashSet> temp=new HashSet>();
  		//先對數組進行排序
  		Arrays.sort(nums);
  		int n=nums.length;
  		//1< list=new ArrayList();
  			for(int j=0;j list:temp)
  		{
  			result.add(list);
  		}
  		return result;
      }
  }