Given a collection of integers that might contain duplicates, S, return all possible subsets.
Note:
For example,
If S = [1,2,2],
a solution is:
[ [2], [1], [1,2,2], [2,2], [1,2], [] ]
public class Solution {
public List<List<Integer>> subsetsWithDup(int[] num) {
Arrays.sort(num);
List<List<Integer>> result=new LinkedList<List<Integer>>();
LinkedList<Integer> subset=new LinkedList<Integer>();
if(num==null) return result;
result.add(subset);
getSubset(num,0,subset,result);
HashSet set=new HashSet(result);
result.clear();
result.addAll(set);
return result;
}
public void getSubset(int []num,int begin,LinkedList<Integer> subset,List<List<Integer>> result){
if(begin==num.length){
return;
}
for(int i=begin;i<num.length;i++){
subset.add(num[i]);
LinkedList<Integer> list=new LinkedList<Integer>();
list.addAll(subset);
result.add(list);
getSubset(num,i+1,subset,result);
subset.pollLast();
}
}
}原文地址:http://blog.csdn.net/dutsoft/article/details/38562193