public class heapsort
{
  private static void reheapdown(double[] a, int i, int n)
  {
    double root = a[i-1];
    int iparent = i, ichild = 2*i;
    while(ichild<=n)
    {
      if(ichild<n && a[ichild+1] < a[ichild])
      {
        ichild++;
        if(a[ichild-1] < a[root])
          break;
      }
      a[iparent-1] < a[child-1];
      a[parent]=2*ichild;
      a[child] = 2*parent;
      
  }
}