Линейный список

program prog;
 
type
  TNode = record
    data: Integer;
    next: ^TNode;
  end;
 
  TList = record
    head: ^TNode;
    tail: ^TNode;
    size: Integer;
  end;
 
 
procedure ListInit(var list: TList);
begin
  list.head:= nil;
  list.tail:= nil;
  list.size:= 0;
end;
 
 
procedure ListPushBack(var list: TList; data: Integer);
begin
  if list.head = nil then begin
    New(list.head);
    list.head^.data:= data;
    list.head^.next:= nil;
    list.tail := list.head;
  end
 
  else begin
    New(list.tail^.next);
    list.tail:= list.tail^.next;
    list.tail^.data:= data;
    list.tail^.next:= nil;
  end;
 
  Inc(list.size);
end;
 
 
procedure ListWrite(const list: TList);
var
  node: ^TNode;
begin
  node:= list.head;
 
  while node <> nil do begin
    Write(node^.data, ' ');
    node:= node^.next;
  end;
 
  WriteLn;
end;
 
 
procedure ListFree(var list: TList);
var
  node: ^TNode;
begin
  while list.head <> nil do begin
    node:= list.head^.next;
    Dispose(list.head);
    list.head:= node;
  end;
end;
 
 
procedure ListMerge(const list1: TList; const list2: TList; var targetList: TList);
var  
  node1, node2: ^TNode;
begin  
  node1:= list1.head;
  node2:= list2.head;
 
  while true do begin
    if node2^.data < node1^.data then begin
      ListPushBack(targetList, node2^.data);
      node2:= node2^.next;
    end  
    else begin
      ListPushBack(targetList, node1^.data);
      node1:= node1^.next;
    end;
      
    if node1 = nil then begin      
      while node2 <> nil do begin
        ListPushBack(targetList, node2^.data);
        node2:= node2^.next;
      end;
      Exit;
    end;
    
    if node2 = nil then begin
      while node1 <> nil do begin
        ListPushBack(targetList, node1^.data);
        node1:= node1^.next;
      end;      
      Exit;
    end;
  end;    
end;
 
 
var
  n: Integer;
  list1, list2, list3: TList;
begin    
  ListInit(list1);
  for n:= -5 to 5 do
    ListPushBack(list1, n);
 
  ListInit(list2);  
  for n:= 1 to 10 do
    ListPushBack(list2, n);
 
  ListInit(list3);
  ListMerge(list1, list2, list3);
    
  ListWrite(list1);
  ListWrite(list2);
  ListWrite(list3);
 
  ListFree(list1);
  ListFree(list2);
  ListFree(list3);
end.