#include <iostream>
#include <string.h>
#include <cstdio>
#include <algorithm>
using namespace std;
#define LL long long
int n , a[15];
bool l[15];

inline void print()
{
for (int i = 0 ; i < n ; ++i)
{
putchar(a[i] + 48);
putchar(32);
}
putchar(10);
}

void f(int m)
{
if (m == n)
{
print();
return;
}
for (int i = 1 ; i <= n ; ++i)
{
if (l[i])
continue;
l[i] = 1;
a[m] = i;
f(m + 1);
l[i] = 0;
}
return;
}

int main()
{
memset(l , 0 , sizeof(l));
cin >> n;
f(0);
return 0;
}

亲测AC，不对我吃

#include <bits/stdc++.h>
using namespace std;
const int N=1e5+10;
int a,n[N];
int vis[N];
void f(int id){
	if(id>a){
		for(int i=1;i<=a;i++){
			cout<<n[i]<<' ';
		}
		cout<<endl;
		return ;
	}
	for(int i=1;i<=a;i++){
		if(vis[i]==1){
			continue;
		}
		n[id]=i;
		vis[i]=1;
		f(id+1);
		vis[i]=0;
	}
}
int main(){
	cin>>a;
	f(1);
	return 0;
}

#include <iostream>
#include <string.h>
#include <cstdio>
#include <algorithm>
using namespace std;
#define LL long long
int n , a[15];
bool l[15];
 
inline void print()
{
	for (int i = 0 ; i < n ; ++i)
	{
		putchar(a[i] + 48);
		putchar(32);
	} 
	putchar(10);
}
 
void f(int m)
{
	if (m == n)
	{
		print();
		return;
	}
	for (int i = 1 ; i <= n ; ++i)
	{
		if (l[i])
			continue;
		l[i] = 1;
		a[m] = i;
		f(m + 1);
		l[i] = 0;
	}
	return;
}
 
int main()
{
	memset(l , 0 , sizeof(l));
	cin >> n;
	f(0);
	return 0;
}