这是一个典型的深度优先搜索问题
class Solution {
private:
void dfs(vector<int>& tmp,vector<vector<int>>& ans,vector<int>& nums,int depth,int n){
if(depth==n){
ans.push_back(tmp);
return;
}
tmp.push_back(nums[depth]);
dfs(tmp,ans,nums,depth+1,n);
tmp.pop_back();
dfs(tmp,ans,nums,depth+1,n);
}
public:
vector<vector<int>> subsets(vector<int>& nums) {
vector<vector<int>> ans;
vector<int> tmp;
int n=nums.size();
dfs(tmp,ans,nums,0,n);
return ans;
}
};
#include "stdafx.h"
#include "vector"
#include "iostream"
using namespace std;
int _tmain(int argc, _TCHAR* argv[])
{
vector<int> vct;
vector<vector<int>> cap;
cap.push_back(vct);
cap.push_back(vct);
cout<<cap.size()<<endl;//此时输出为2,即使是空的容器,也占用一个位置
return 0;
}