Subsets II (leetcode)

题目：

Given a collection of integers that might contain duplicates, 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 = [1,2,2], a solution is:

[  [2],  [1],  [1,2,2],  [2,2],  [1,2],  []]

方法：把vector中的数不断取出来，然后加一位再添到最后。

代码：

#include<iostream>#include<vector>#include<algorithm>using namespace std;vector<vector<int> > subsetsWithDup(vector<int> &S){vector<vector<int> > results;if(S.empty())return results;sort(S.begin(),S.end());for(int i=0;i<S.size();i++){int size=results.size();for(int j=0;j<size;j++){vector<int> result=results[j];result.push_back(S[i]);results.push_back(result);}results.push_back(vector<int> (1,S[i]));}sort(results.begin(),results.end());results.erase(unique(results.begin(),results.end()),results.end());results.push_back(vector<int>(0));return results;}int main(){vector<int> S(3);S[0]=0;S[1]=2;S[2]=3;vector<vector<int> > results=subsetsWithDup(S);system("pause");return 0;}