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],  []]

 

 Code:

class Solution {public:    void findSub(vector
          
            &S, int &n, int level, vector
           
             &buf, vector
            
             
              > &res){        if(buf.size()==n){            res.push_back(buf);            return;        }        for(int i=level;i
              

> subsets(vector

&S) { vector

> res; vector

buf; sort(S.begin(),S.end()); for(int i=0;i<=S.size();i++) findSub(S,i,0,buf,res); return res; }};