Subsets

class Solution {
public:
    vector<vector<int>> subsets(vector<int>& nums) 
    {
        vector<vector<int>> res;
        vector<int> emp;
        res.push_back(emp);
        sort(nums.begin(), nums.end());
        if(nums.size()==0)
            return res;
        
        for(vector<int>::iterator iter=nums.begin();iter!=nums.end();++iter)
        {
            int size=res.size();
            for(int i=0;i<size;++i)
            {
                vector<int> temp=res[i];
                
                temp.push_back(*iter);
                res.push_back(temp);
            }
        }
        
        return res;
    }
};

http://www.cnblogs.com/felixfang/p/3775712.html