题解，两种

//偷鸡代码,CSP别用
#include<iostream>
using namespace std;
int main(){
    int n;
	cin>>n;
	if(n==1) cout<<1;
	if(n==2) cout<<1<<" "<<2<<endl<<2<<" "<<1;
	if(n==3){
		cout<<1<<" "<<2<<" "<<3<<endl;
		cout<<1<<" "<<3<<" "<<2<<endl;
		cout<<2<<" "<<1<<" "<<3<<endl;
		cout<<2<<" "<<3<<" "<<1<<endl;
		cout<<3<<" "<<1<<" "<<2<<endl;
		cout<<3<<" "<<2<<" "<<1;
	}
	return 0;
}

//正常代码,CSP随便用
#include<iostream>
using namespace std;
int a[101],n; //a[101]记录每一种全排列的情况.
int vis[101]; //标记这个数没有被选过.0为没选过,1为选过.
void dfs(int x){
    if(x==n){
        for(int i=0;i<n;i++) cout<<a[i]<<" ";
        cout<<"\n";
        return ;
    }
    for(int i=1;i<=n;i++){
        if(!vis[i]){
            vis[i]=1;
            a[x]=i;
            dfs(x+1);
            vis[i]=0;
        }
    }
}
int main(){
	cin>>n;
    dfs(0);
	return 0;
}