C++ :

#include <stdio.h>
#include <math.h>
#include <assert.h>

#define N 1000

double x[100], y[100], xx, yy, base,scale;
int rep,n,i,j,k,T;

int main(){
   double minx, maxx, miny, maxy, dx, dy, dd, best; int besti;
   scanf("%d\n",&T);
   while (T--) {
      assert (1 == scanf("%d",&n));
      for (i=0;i<n;i++) scanf("%lf%lf",&x[i],&y[i]);
      best = 1000;
      base = 0; scale=1;
      for (rep=0;rep<10;rep++) {
         besti = 0;
         for (i=0;i<N;i++) {
            double sininc = sin(base+scale*i*M_PI/2/N);
            double cosinc = cos(base+scale*i*M_PI/2/N);
            maxx = maxy = -1e99; minx = miny = 1e99;
            for (j=0;j<n;j++){
               xx = cosinc*x[j] - sininc*y[j];
               yy = sininc*x[j] + cosinc*y[j];
               //printf("x y xx yy %lg %lg %lg %lg\n",x[j],y[j],xx,yy);
               if (xx < minx) minx = xx;
               if (xx > maxx) maxx = xx;
               if (yy < miny) miny = yy;
               if (yy > maxy) maxy = yy;
            }
            dx = maxx - minx;
            dy = maxy - miny;
            dd = dx;
            if (dy > dd) dd = dy;
            if (dd < best) {
               best = dd;
               besti = i;
            }
            //printf("i %d dd %0.5lf\n",i,dd);
         }
         base += scale*(besti-1)*M_PI/2/N;
         scale = scale/N*2;
      }
      printf("%0.2lf\n",best*best);
   }
   //assert(1 != scanf(" %c",&i));
}