[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;

       

    }

};