#include<iostream>#include<vector>using namespace std;void solution(int i,vector<int> &nums,vector<int> &item,vector<vector<int> > &result) //传引用 { if(i >= nums.size()) return ; item.push_back(nums[i]); result.push_back(item); solution(i+1,nums,item,result); item.pop_back(); solution(i+1,nums,item,result);}int main(){ vector<int> nums; nums.push_back(1); nums.push_back(2); nums.push_back(3); vector<int> item; vector<vector<int> >result; int i = 0; result.push_back(item); //将空集push进result solution(i,nums,item,result); for(int i = 0; i < (1<< nums.size()); i++) { if(result[i].size() == 0) { cout<<"[]"; } for(int j = 0; j < result[i].size(); j++) { cout<<"["<<result[i][j]<<"]"; } cout<<endl; }}