procedure genheap(f:ftype;Heap:integer);
var i,temp,j,k:integer;
begin
for k:=1 to Heap div 2 do
begin
  for i:=1 to Heap div 2 do
    begin
       if (f[i]<f[i*2]) then
          begin
            temp:=f[i];
            f[i]:=f[i*2];
            f[i*2]:=temp;
          end;
       if (f[i]<f[i*2+1]) and (i*2+1<Heap)then
          begin
            temp:=f[i];
            f[i]:=f[i*2+1];
            f[i*2+1]:=temp;
          end;
    end;
end;
end;

procedure heapsort(f:ftype;n:integer);
var i:integer;
begin
if n>0 then
begin
  genheap(myarray,n);
  for i:=1 to n do
    myarray[i-1]:=myarray[i];
  myarray[n]:=myarray[0];
  heapsort(myarray,n-1);
end;
end;