九度教程第89题

题目地址：http://jobdu.sinaapp.com/problem.php?cid=1040&pid=88

C语言源码：

#include<stdio.h>#include<math.h>int s[18];int mark[18];int pri(int n){int i,b;b=(int)sqrt(n)+1;if(n==2)return 1;i=2;while(i<=b){if(n%i==0)return 0;elsei++;}return 1;}void input(int i,int n){int j,flag;if(i==n+1){flag=0;for(j=1;j<n;j++){if(pri(s[j]+s[j+1])==0){flag=1;break;}}if(pri(s[1]+s[n])==0)flag=1;if(flag==0){for(j=1;j<n;j++)printf("%d ",s[j]);printf("%d\n",s[j]);}}else{for(j=1;j<=n;j++){if(mark[j]==-1&&pri(s[i-1]+j)==1){s[i]=j;mark[j]=1;input(i+1,n);mark[j]=-1;}}}}int main(){int n,num,i;num=1;s[1]=1;while(scanf("%d",&n)!=EOF){for(i=0;i<=n;i++)mark[i]=-1;mark[1]=1;printf("Case %d:\n",num++);input(2,n);printf("\n");}}