Leetcode 90 subsets 2, Lintcode 

Q: 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.

 

java version 1

import java.util.Arrays;public class Solution {    public List
     
      
       > subsetsWithDup(int[] nums) {        List
       
        
         > ans = new ArrayList
         
          
           >(); if (nums == null) return ans; List
           
             ele = new ArrayList
            
             (); Arrays.sort(nums); addElement(ans, ele, nums, 0, nums.length-1); return ans; } public void addElement(List
             
              
               > ans, List
               
                 ele, int[] nums, int start, int end ){ if (start > end){ ans.add(new ArrayList
                
                 (ele)); return; } for(int i = start; i <= end; i++){ if (i > start && nums[i] == nums[i-1]){ continue; }else{ ele.add(nums[i]); addElement(ans, ele, nums, i+1, end); ele.remove(ele.size()-1); } } ans.add(new ArrayList
                 
                  (ele)); return; }}