hdu1016

#include <stdio.h>
#include <string.h>

int prime[38]={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};
int visit[21]={0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
int result[21]={0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};

void print(int* s, int n)
{
int i;
for(i=0;i<n;i++)
{
if(i) printf(" %d",s[i]);
else printf("%d",s[i]);
}
printf(" ");
}

void dfs(int* s, int* c,int i, int n)
{
int k;
if(!i)
{
s[0]=1;
c[1]=1;
dfs(s,c,i+1,n);
c[1]=0;
}
else if(i<n-1)
{

for(k=2;k<=n;k++)
{
if(!c[k] && prime[s[i-1]+k])
{
s[i]=k;
c[k]=1;
dfs(s,c,i+1,n);
c[k]=0;
}
}
}
else if(i==n-1)
{
for(k=2;k<=n;k++)
{
if(!c[k] && prime[s[i-1]+k] && prime[k+1])
{
s[i]=k;
c[k]=1;
dfs(s,c,i+1,n);
c[k]=0;
}
}
}
else if(i==n)
{
print(s, n);
}
}

int main(void)
{
int n,i;
i=1;
while(scanf("%d", &n)!=EOF)
{
printf("Case %d: ",i++);

memset(result,0,21);
memset(visit,0,21);

dfs(result,visit,0,n);
printf(" ");
}
return 0;
}