Subsets [LeetCode]

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],

  []

]

Summary: Recursive approach, we can optimize it.

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

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

         vector<vector<int> > result;

         vector<int> subset;

         result.push_back(subset);

         if(S.size() == )

             return result;

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

             vector<int> sub_s(S.begin() + i + , S.end());

             vector<vector<int> > ret = subsets(sub_s);

             for(auto item : ret){

                 item.insert(item.begin(), S[i]);

                 result.push_back(item);

             }

         }

         return result;

     }

巴特西

Subsets [LeetCode]

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