#include<algorithm>//sort
#include <bits/stdc++.h>;
using namespace std;
int a[10],book[10]={0};
int n;
void dfs(int step)
{
	if(step==n+1)
	{
		for(int i=1;i<=n;i++)
		{
			cout<<"     "a[i];
		}
		cout<<endl;
		return;
	}
	for(int i=1;i<=n;i++)
	{
		if(book[i]==0)
		{
			book[i]=1;
			a[step]=i;
			dfs(step+1);
			book[i]=0;
		}
	}
	return;
}
int main(){
	cin>>n;
	dfs(1);
}

我前面和后面跟五个空格都WA！