leetcode90 Subsets II

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,
If nums = [1,2,2], a solution is:

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

 1 class Solution {
 2 public:
 3     vector<vector<int>> subsetsWithDup(vector<int>& nums) {
 4         sort(nums.begin(),nums.end());
 5         vector<vector<int>> ans;
 6         vector<int> cur;
 7         ans.push_back(cur);
 8         dep(ans,nums,0,cur);
 9         return ans;
10     }
11     void dep(vector<vector<int>>&ans,vector<int>&nums,int pos,vector<int>&cur)
12     {
13         int size=nums.size();
14         if(pos>=size)
15             return;
16         for(int i=pos;i<size;i++)
17         {
18             if(i!=pos&&nums[i]==nums[i-1])
19                 continue;
20             
21             cur.push_back(nums[i]);
22             ans.push_back(cur);//解决自某个元素后都不选则添加不进结果集的情况
23             dep(ans,nums,i+1,cur);
24             cur.erase(cur.end()-1);
25         }
26     }
27 };

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