#include<iostream>
#include<vector>
using namespace std;
vector<vector<int> > result;
int cnt;
void solution(vector<int> nums)
{
int num=1;
cnt = (1 << nums.size());
for(int i = 0; i < cnt; i++)
{
vector<int> item;
for(int j = 0; j < nums.size(); j++)
{
if(i & (1 << j))
{
item.push_back(nums[j]);
}
}
result.push_back(item);
}
}
int main()
{
vector<int> nums;
nums.push_back(1);
nums.push_back(2);
nums.push_back(3);
solution(nums);
for(int i = 0; i < cnt; i++)
{
if(result[i].size() == 0)
{
cout<<"[]";
}
for(int j = 0; j < result[i].size(); j++)
{
cout<<"["<<result[i][j]<<"]";
}
cout<<endl;
}
return 0;
} 原文：https://blog.51cto.com/14472348/2471590