UVa 152 Tree's a Crowd

UVa 152 Tree's a Crowd

给出若干个三维空间中点的坐标，如果某个点到其他点的欧几里德距离（向下取整）小于10，则统计这个距离。
以下是我的代码：

#include < cstdio >
#include < cstdlib >
#include < cmath >
using   namespace  std;
const   int  kMaxn( 5007 );
const   int  kInf( 0x7f7f7f7f );

struct  Point
{
     int  x,y,z;
}r[kMaxn];

int  main()
{
     /*
    freopen("data.in","r",stdin);
    freopen("data.out","w",stdout);
    // */

     int  n( 0 ),x,y,z;
     while (scanf( " %d%d%d " , & x, & y, & z) == 3   &&  (x  ||  y  ||  z))
    {
        n ++ ;
        r[n].x = x;
        r[n].y = y;
        r[n].z = z;
    }

     int  d[ 17 ] = { 0 };
     for ( int  i = 1 ;i <= n;i ++ )
    {
         int  distance(kInf);
         for ( int  j = 1 ;j <= n;j ++ )
        {
             if (i == j)  continue ;
             int  s(( int )sqrt((r[i].x - r[j].x) * (r[i].x - r[j].x) + (r[i].y - r[j].y) * (r[i].y - r[j].y) + (r[i].z - r[j].z) * (r[i].z - r[j].z)));
             if (distance > s)
                distance = s;
        }
         if (distance <= 9 )
            d[distance] ++ ;
    }

     for ( int  i = 0 ;i <= 9 ;i ++ )
        printf( " %4d " ,d[i]);
    printf( " \n " );

     return   0 ;
}