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],

  []

]
思路：这道题在Subsets基础上，添加了重复元素，然而在最后的结果当中不能有重复的vector出现，也就是在组合这些整数的时候要加一些限制条件。

class Solution {

public:

    void find(vector<vector<int> > &result,vector<int> &S,vector<int> data,int index)

    {

        result.push_back(data);

        for(int i=index;i<S.size();i++)

        {

            if(i!=index&&S[i]==S[i-1])

                continue;

            data.push_back(S[i]);

            find(result,S,data,i+1);

            data.pop_back();

        }

    }

    vector<vector<int> > subsetsWithDup(vector<int> &S) {

        vector<vector<int> > result;

        vector<int> data;

        result.clear();

        if(S.empty())

            return result;

        sort(S.begin(),S.end());

        find(result,S,data,0);

        return result;

    }

};