codevs——1294 全排列

#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<iostream>
#include<algorithm>
using namespace std;
bool vis[100];
int n,a[100];
int read()
{
    int x=0,f=1; char ch=getchar();
    while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1; ch=getchar();}
    while(ch>=‘0‘&&ch<=‘9‘){x=x*10+ch-‘0‘; ch=getchar();}
    return x*f;
}
void dfs(int now)
{
    if(now==n+1) 
    {
        for(int i=1;i<=n;i++)
         printf("%d ",a[i]);
        printf("\n");
        return ;
    }
    for(int i=1;i<=n;i++)
     if(!vis[i])
     {
         vis[i]=true;
         a[now]=i;
         dfs(now+1);
         vis[i]=false;
     }
    return ;    
}
int main()
{
    n=read();
    dfs(1);
    return 0;
}