HDOJ1016(标准dfs)

#include <iostream> 
#include <cstdio>
#include <cstring>
using namespace std;
int isPrime[40]={0,0,1,1,0,1,0,1,0,0,0,1,0,1,0,0,0,1,0,1,0,0,0,1,0,0,0,0,0,1,0,1,0,0,0,0,0,1,0,1}; 
int vis[21];
int A[21];

void dfs(int index,int n)
{
    if(index==n&&isPrime[A[index-1]+A[0]])
    {
        printf("%d",A[0]);
        for(int i=1;i<n;i++)
            printf(" %d",A[i]);
        printf("\n");
        return ;
    }
    for(int i=2;i<=n;i++)
    {
        if(!vis[i]&&isPrime[i+A[index-1]])
        {
            vis[i]=1;
            A[index]=i;
            dfs(index+1,n);
            vis[i]=0;
        }
    }
    
}

int main()
{
    int n;
    int T=0;
    while(scanf("%d",&n)!=EOF)
    {
        printf("Case %d:\n",++T);
        if(n%2==1)
            continue;
        memset(A,0,sizeof(A));
        A[0]=1;
        dfs(1,n);
        printf("\n");
    }
    
    
    return 0;
}