```c
printf("%3d%3d%3d\n",a[0],a[1],a[2]);
```
3不能放在%和d中间。
by Hedabo_2509 @ 2022-11-30 19:56:50
@[Hedabo_2509](/user/712075) 没有问题啊，重定义
by simonG @ 2022-11-30 19:57:25
@[gaosichensb](/user/253936)
```c
printf("%3d%3d%3d\n",a[0],a[1],a[2]);
```
这里？（我是菜鸡，谢谢大佬指点
by Hedabo_2509 @ 2022-11-30 19:58:45
@[Hedabo_2509](/user/712075) 我说 ```sort``` 没问题
by simonG @ 2022-11-30 19:59:31
@[gaosichensb](/user/253936) 我知道你的意思是sort没错，但是“%3d"错了吧？
by Hedabo_2509 @ 2022-11-30 20:00:24
@[Hedabo_2509](/user/712075) 没错，很常见的写法 %3d是向右靠齐3格，%-3d是向左
by Feng_Jing @ 2022-11-30 20:18:47
sort(num)里面再sort（num)，num值没有改变，不会死循环嘛
by EineKliene @ 2023-02-20 19:28:22
# [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 20:53:31