hdu 1874 畅通工程续

#include<stdio.h>
#include<math.h>
#include<stdlib.h>
struct E
{
       int x,y,set;
}e[124];
struct val
{
       int a,b;
       double dis;
}va[10000];
int t,c,count;
int cmp( const void *a,const void *b )
{
    return ((val *)a)->dis > ((val *)b)->dis ? 1 : -1;
}
int find( int i )
{
    return e[i].set == i ? i : e[i].set = find( e[i].set );
}
double Krustra( ){
       double sum = 0;
       for( int  i = 1 ; i <= count; ++i )
       {
            int a = va[i].a,b = va[i].b;
            a = find( a ),b = find( b );
            if( a != b )
            {
                sum += va[i].dis;
                e[a].set = b;
            }
        }
        return sum;
       }
int main( )
{
    scanf( "%d",&t );
    while( t-- )
    {
           scanf( "%d",&c );
           count = 0;
           for( int i = 0; i <= c; ++i )
                e[i].set = i;
           for( int i = 1; i <= c; ++i )
           {
                scanf( "%d%d",&e[i].x,&e[i].y );
            }
            for( int i = 1; i < c; ++i )
            {
                 for( int j = i + 1; j <= c; ++j )
                 {
                      double a = e[i].x - e[j].x,b = e[i].y - e[j].y;
                      double dis = sqrt( a * a + b * b );
                      if( dis >= 10 && dis <= 1000 )
                      {
                          ++count;
                          va[count].a = i,va[count].b = j,va[count].dis = dis;
                      }
                  }
             }
             qsort( va + 1,count,sizeof( va[1] ),cmp );
             double res = Krustra();
             int k = 0;
             for( int i = 1; i <= c; ++i )
             {
                  if( e[i].set == i )
                      ++k;
                  if( k > 1 )
                      break;
              }
            if(  k == 1)
                 printf( "%.1lf\n",res * 100 );    
            else
                 printf( "oh!\n" );
           }
    return 0;
}