【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,,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+,tmp);

         tmp.push_back(S[index]);

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

     }

 };