# [个人博客主页](https://www.ricemoon.cn/)
```cpp
#include <bits/stdc++.h>
using namespace std;
const int N = 1e6 + 10;
typedef pair<int, int> PII;
int n, r;
int path[30];
bool st[30];
void dfs(int u, int num)
{
if (u == r + 1)
{
for (int i = 1; i <= r; i ++) cout << setw(3) << path[i];
cout << endl;
}
for (int i = 1; i <= n; i ++)
{
if (!st[i] and i > num)
{
st[i] = true;
path[u] = i;
dfs(u + 1, path[u]);
st[i] = false;
path[u] = 0;
}
}
}
int main()
{
cin >> n >> r;
dfs(1, 0);
return 0;
}
```
by Roger_Spencer @ 2023-03-05 20:53:48