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  1 #include<stdio.h>
  2 #include<math.h>
  3 #include<string.h>
  4 #define M 999999999
  5 #define N 2000000
  6 int a[610],map[610][610];
  7 int b[610],c[610],g[N];
  8 int Min(int x,int y)
  9 {
 10     if(x>y)
 11         return y;
 12     else
 13         return x;
 14 }
 15 void prim()
 16 {
 17     int i,j;
 18     int flag=1;
 19     memset(g,0,sizeof(g));
 20     g[0]=1;g[1]=1;
 21     for(i=2;i<=N;i++)
 22     {
 23         if(!g[i])
 24         {
 25             for(j=i+i;j<=N;j+=i)
 26                 g[j]=1;
 27         }
 28     }
 29 }
 30 int fun(int x,int y)
 31 {
 32     if(!g[x]||!g[y]||!g[x+y])
 33         return 1;
 34     else
 35         return 0;
 36 }
 37 int main()
 38 {
 39     int tt,n,i,j,x,y;
 40     scanf("%d",&tt);
 41 
 42     prim();
 43     while(tt--)
 44     {
 45         scanf("%d",&n);
 46         for(i=1;i<=n;i++)
 47             scanf("%d",&a[i]);
 48         memset(map,0,sizeof(map));
 49         memset(b,0,sizeof(b));
 50         
 51         for(i=1;i<=n;i++)
 52         {
 53             for(j=i+1;j<=n;j++)
 54             {
 55                 map[i][j]=map[j][i]=M;
 56                     if(fun(a[i],a[j]))
 57                     {
 58                         x=Min(a[i],a[j]);
 59                         if(a[i]>a[j])
 60                             y=a[i]-a[j];
 61                         else
 62                             y=a[j]-a[i];
 63                         
 64                         map[i][j]=map[j][i]=Min(x,y);
 65                     }
 66             }
 67         }
 68         c[1]=0;
 69         for(i=2;i<=n;i++)
 70             c[i]=map[1][i];
 71         int t,flag=0;
 72         t=1;
 73         c[t]=0;
 74         int sum=0;
 75         while(b[t]==0)
 76         {
 77             b[t]=1;
 78             for(i=1;i<=n;i++)
 79                 if(b[i]==0&&c[i]>map[t][i])
 80                     c[i]=map[t][i];
 81                 int min=M;
 82                 for(i=1;i<=n;i++)
 83                     if(b[i]==0&&min>c[i])
 84                     {
 85                         min=c[i];
 86                         t=i;
 87                     }
 88                     if(min!=M)
 89                     {
 90                         sum+=min;
 91                     }
 92                     
 93         }
 94         for(i=1;i<=n;i++)
 95         {
 96             if(c[i]>=M)
 97             {
 98                 flag=1;
 99                 break;
100             }
101         }
102         if(flag==0)
103             printf("%d\n",sum);
104         else
105             printf("-1\n");
106     }
107     return 0;
108 }

 

posted @ 2013-05-03 17:59  zlyblog  阅读(174)  评论(0)    收藏  举报