C++ 代码

#include<bits/stdc++.h>
using namespace std;

int n;
int now = 0;
int choice[15];

void func(int x){
    if(x > n){
        for(int i = 0; i < now; i++){
            if(i != 0)
                cout << " ";
            cout << choice[i];
        }
        cout << endl;
        return ;
    }
    func(x + 1);
    choice[now++] = x;
    func(x + 1);
    now--;
}

int main(){
    cin >> n;
    func(1);
    return 0;
}