[LeetCode系列]子集枚举问题[有重复元素]

 1 class Solution {
 2 public:
 3     vector<vector<int> > subsetsWithDup(vector<int> &S) {
 4         sort(S.begin(), S.end());
 5         vector<vector<int>> result(1);
 6         int oldval=S[0];
 7         int oldj=0;
 8         for(int i=0; i<S.size(); i++){
 9             int temp=oldj;
10             if(S[i]!=oldval){
11                 oldval=S[i]; temp=0;
12             }
13             int j=result.size();
14             oldj=j;
15             while(j-->temp){
16                 //note temp here help avoid creating duplicate subsets
17                 result.push_back(result[j]);
18                 result.back().push_back(S[i]);
19             }
20         }
21         return result;
22     }
23 };