Given a collection of integers that might contain duplicates, S, return all possible subsets.
Note:
For example,
If S = [1,2,2], a solution is:
[ [2], [1], [1,2,2], [2,2], [1,2], [] ]
Array Backtracking
class Solution { private: vector<vector<int> > ret; public: void generate(vector<int> vet,vector<int> &S,int i){ if(i==S.size()){ for(int k=0;k<ret.size();k++){ if(vet==ret[k]) //去除重复 return; } ret.push_back(vet); return; } generate(vet,S,i+1); //相当于取右子树 vet.push_back(S[i]); generate(vet,S,i+1); //相当于取左子树 } vector<vector<int> > subsetsWithDup(vector<int> &S) { sort(S.begin(),S.end()); generate(vector<int>(),S,0); return ret; } };
原文：http://www.cnblogs.com/li303491/p/4112629.html