【leetcode】Subsets

Subsets

Given a set of distinct integers, 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 = [1,2,3], a solution is:

[
  [3],
  [1],
  [2],
  [1,2,3],
  [1,3],
  [2,3],
  [1,2],
  []
]

采用递归，取当前元素，或者不取当前元素。

class Solution {

public:

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

       

        vector<vector<int> > result;

        vector<int> tmp;

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

        getSubset(result,S,0,tmp);

        return result;

    }

   

    void getSubset(vector<vector<int> > &result,vector<int> &S,int index,vector<int> tmp)

    {

        if(index==S.size())

        {

            result.push_back(tmp);

            return;

        }

       

        getSubset(result,S,index+1,tmp);

        tmp.push_back(S[index]);

        getSubset(result,S,index+1,tmp);

       

    }

};