[leetcode]Subsets II

 

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

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

这个曾经让我很捉鸡的题目。。。为什么这次用了个很烂的dfs，一次性通过，而且是80ms过大集合。。。。太讽刺了。。。

class Solution {
    set<vector<int>> result;
public:
    void dfs(vector<int>&S, int i, vector<int> tmp){
        if(i == S.size()){
            sort(tmp.begin(), tmp.end());
            result.insert(tmp);
            return;
        }
        dfs(S, i+1, tmp);
        
        tmp.push_back(S[i]);
        dfs(S, i+1, tmp);
        
        
    }
    

    vector<vector<int> > subsetsWithDup(vector<int> &S) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        result.clear();
        vector<int> tmp;
        dfs(S, 0, tmp);
        set<vector<int>>::iterator it;
        
        vector<vector<int>> ret;
        for(it = result.begin(); it!=result.end(); it++){
            ret.push_back(*it);
        }
        
        return ret;
       
    }
};