пирамедальная сортировка

program Project1;

const
  Dlina = 251;

type
  Telem=shortint;
  Tdlina= byte;
  mas= array [0..Dlina-1] of Telem;

procedure downHeap(var a: mas; k,n: Tdlina);
  {  ïðîöåäóðà ïðîñåèâàíèÿ ñëåäóþùåãî ýëåìåíòà}
  {  Äî ïðîöåäóðû: a[k+1]...a[n]  - ïèðàìèäà }
  {  Ïîñëå:  a[k]...a[n]  - ïèðàìèäà }
var
  new_elem: Telem;
  child: Tdlina;
  flag: boolean;
begin
  new_elem := a[k];
  flag:=true;

  while(k <= n/2) and flag do  { ïîêà ó a[k] åñòü äåòè }
  begin
    child := 2*k;
    {  âûáèðàåì áîëüøåãî ñûíà}
    if( child < n) and (a[child] < a[child+1] ) then
      inc(child);
    if( new_elem >= a[child] ) then flag:=false
    else     { èíà÷å}
      begin a[k] := a[child];     { ïåðåíîñèì ñûíà íàâåðõ}
            k := child;
      end;
  end;
  a[k] := new_elem;
end;


procedure heapSort(var a: mas; size:Tdlina);
var
  i: Tdlina;
  temp: Telem;
begin
  { ñòðîèì ïèðàìèäó }
  for i:=size div 2 - 1 downto 0 do downHeap(a, i, size-1);

  { òåïåðü a[0]...a[size-1] ïèðàìèäà}

  for i:=size-1 downto 1 do
  begin
    { ìåíÿåì ïåðâûé ñ ïîñëåäíèì }
    temp:=a[i]; a[i]:=a[0]; a[0]:=temp;

    { âîññòàíàâëèâàåì ïèðàìèäàëüíîñòü a[0]...a[i-1] }
    downHeap(a, 0, i-1);
  end
end;


var
  massiv: mas;
  i,size: Tdlina;

begin
  randomize;
  repeat
    write('size (1..',Dlina,')=?'); readln(size);
  until (size>0) and (size<=Dlina);
  for i:=0 to size-1 do
    massiv[i]:=random(256)-128;

  writeln('Massiv:');
  for i:=0 to size-1 do
    write(massiv[i],' ');
  writeln;

  heapSort(massiv, size);

  writeln('Massiv:');
  for i:=0 to size-1 do
    write(massiv[i],' ');
  writeln;

  write('Press Enter...');readln
end.