素数环 问题PE 求解~~

Question

输出格式错误了，不知道题目对格式的具体要求
附上代码：
#include
#include
#include
using namespace std;
int prime[40]={1,1,0,0,1,0,1,0,1,1,1,0,1,0,1,1,1,0,1,0,1,1,1,0,1,1,1,1,1,0,1,0,1,1,1,1,1,0,1,1};
int n;
int a[20];
int mark[20];
int cnt,flag;
void dfs(int x)
{
if (x > 0 && a[0] != 1) return;//使第一个数固定为一
if (x == n && !prime[a[x-1] + a[0]]/* && a[0] == 1*/){//当首尾相连时候，判断，成功就打印
if(flag) printf("Case %d:\n",cnt++);
flag=0;
printf("%d",a[0]);
for(int i = 1; i < n; ++i){
printf(" %d",a[i]);
}
printf("\n");
}
for (int i = 1; i <= n; ++i){
if (!x||(!prime[a[x-1] + i] && !mark[i])){
mark[i]=1;
a[x]=i;
dfs(x+1);
mark[i]=0;
}
}
}
int main()
{
cnt=1;
while(scanf("%d",&n) && n){
if(n%2 ==1 && n != 1)
{
printf("Case %d:\n",cnt++);
printf("No Answer\n");
continue;
}
memset(mark,0,sizeof(mark));
flag=1;
dfs(0);
if (flag){
printf("Case %d:\n",cnt++);
printf("No Answer\n");
}
}
return 0;
}

Answer 1

http://blog.csdn.net/slience_perseverance/article/details/6695423