program DSA_U1;

type DvipSar = ^dvipElem;
     dvipElem = record
                    info : integer;
                    next : DvipSar;
                    previous : DvipSar;
                    key : integer;
                end;

procedure sukurti(var pradzia, pabaiga : DvipSar; var kiekis : integer);

var klaida, info, ct : integer;
    laikinas : DvipSar;
    input : string;

begin
    kiekis := 0;
    writeln('Iveskite ', kiekis + 1,'-aji saraso elementa. Noredami nutraukti ivedima, rasykite ''stop''');
    readln(input);
    val(input, info, klaida);

    if klaida = 1
    then writeln('Jus ivedete ne skaiciu, prasome ivesti skaiciu')
    else
    if (klaida = 0) and (input <> 'stop') then
    begin
        new(laikinas);
        laikinas^.info := info;
        pradzia := laikinas;
        pabaiga := laikinas;
        laikinas^.next := nil;
        laikinas^.previous := nil;
        kiekis := kiekis + 1;
        ct := 1;
    end;


    while input <> 'stop' do
    begin
        writeln('Iveskite ', kiekis + 1,'-aji saraso elementa. Noredami nutraukti ivedima, rasykite ''stop''');
        readln(input);
        val(input, info, klaida);
        if klaida = 0 then
        begin
            if kiekis >= 1 then
            new(laikinas);
            laikinas^.next := pradzia;
            pradzia := laikinas;
            laikinas^.next^.previous := pradzia;
            laikinas^.info := info;
            ct := ct + 1;
            laikinas^.key := ct;
            kiekis := kiekis + 1;
        end
        else
        if (klaida = 1) and (input <> 'stop')
        then writeln('Jus ivedete ne skaiciu, prasome ivesti skaiciu');
    end;
    pradzia^.previous := nil;
//writeln('kgahjkglajg ', laikinas^.info);
end;

procedure spausdinti(laikinas : DvipSar);
begin
   // laikinas := pradzia;
    while laikinas <> nil do
    begin
        writeln(laikinas^.info);
        laikinas := laikinas^.previous;
    end;
end;



procedure swap(elementas1, elementas2 : DvipSar);
var temp : integer;

begin
    temp := elementas1^.info;
    elementas1^.info := elementas2^.info;
    elementas2^.info := temp;
end;


//procedure siftDown(laikinas : DvipSar; start, endz : integer)
//var root, a, b : integer;     //input:  end represents the limit of how far down the heap
//begin    //               to sift.
//    root := laikinas^.pradzia^.key;
//    laikinas := pradzia;
//    while root * 2 + 1 <= endz do          //(While the root has at least one child)
//    begin
//        a := laikinas^.info;
//        b := laikinas^.next^.info;
//        child := root * 2 + 1            //(root*2+1 points to the left child)
//        // (If the child has a sibling and the child's value is less than its sibling's...)
//        if (child < endz) and (a < b) then
//        begin
//            laikinas := laikinas^.next;           //(... then point to the right child instead)
//        end
//        if pradzia^.info < laikinas^.info then       //(out of max-heap order)
//        begin
//            swap(laikinas^.pradzia^.info, laikinas^.info);
//            //pradzia^.info := laikinas^.info;                //(repeat to continue sifting down the child now)
//        end
//end;


//procedure heapSort(laikinas : DvipSar; kiekis : integer);
//var endz : integer;
//begin
//     heapify(pradzia, kiekis);
//
//     endz := kiekis - 1;
//     while endz > 0 do
//         //(swap the root(maximum value) of the heap with the last element of the heap)
//         swap(a[endz], a[0])
//         //(decrease the size of the heap by one so that the previous max value will
//         //stay in its proper placement)
//         endz := endz - 1
//         //(put the heap back in max-heap order)
//         siftDown(a, 0, endz)
//end;

//procedure heapify(laikinas : DvipSar, kiekis : integer)
//var integer : start;    // (start is assigned the index in a of the last parent node)
//begin
//     start := kiekis / 2 - 1
//
//     while start >= 0 do
//     begin
//       //  (sift down the node at index start to the proper place such that all nodes below
//      //    the start index are in heap order)
//         siftDown(pabaiga, start, kiekis-1)
//         start := start - 1
//     //(after sifting down the root all nodes/elements are in heap order)
//     end;
//end;

procedure heapify(laikinas : DvipSar; kiekis : integer);
var laponr, l, r, largest : integer;
begin
    l:=1; r:=1;
    while laikinas <> nil do
    begin
        if (l <= kiekis) and laikinas^.larg > laikinas^.












////////////////////

var pradzia, pabaiga : DvipSar;
    kiekis : integer;

begin
    writeln('Programa sarase suranda maziausia elementa ir ji pasalina.');
    writeln;
    sukurti(pradzia, pabaiga, kiekis);
    writeln('');
    writeln('Jusu ivestas sarasas: ');
    spausdinti(pabaiga);


    //spausdinti(pirmas, kiekis);
    readln;
end.