极限压缩！

#include<bits/stdc++.h>
using namespace std;int n;int a[114514],vis[114514];void dfs(int x){if(x>n){for(int i=1;i<=n;i++) cout<<a[i]<<" ";cout<<endl;return ; }for(int i=1;i<=n;i++){ if(vis[i]==0){vis[i]=1;a[x]=i;dfs(x+1);vis[i]=0;}}}int main(){cin>>n;dfs(1);return 0;}