题解

#include <iostream>
#include <cstdio>
using namespace std;
int n;
int book[15];
int step[15];
void dfs(int x)
{
    if(x>n){
        for(int i=1;i<=n;i++){
            
               printf("%d ",step[i]);
        }
        cout<<endl;
        return;
    }
    for(int i=1;i<=n;i++){
        if(book[i]==0){
            book[i] = 1;  
            step[x] = i;
            dfs(x+1);
            book[i] = 0;
        }
    }
}
int main()
{
    cin>>n;
    dfs(1);
    return 0;
}