由于Delphi官方没有实现优先队列容器，我自己也懒得用二叉堆去实现，这里用List简单实现一个优先队列；
unit Unit3;
interface
uses
Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
Vcl.Controls, Vcl.Forms, Vcl.Dialogs, System.Generics.Collections, System.Generics.Defaults,
Vcl.StdCtrls, System.SyncObjs;
type
TForm3 = class(TForm)
btn1: TButton;
mmo1: TMemo;
procedure btn1Click(Sender: TObject);
procedure FormCreate(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
TPerson = class
private
name: string;
age: Integer;
public
constructor Create(name: string; age: Integer);
end;
/// <summary>
/// 优先队列 - List，入队慢，出队快模式
/// </summary>
TPriorityQueue<T> = class
private
list: TList<T>;
public
constructor Create(const Comparison: TComparison<T>);
destructor Destroy; override;
function Dequeue: T;
procedure Enqueue(item: T);
function Count: Integer;
end;
var
Form3: TForm3;
implementation
{$R *.dfm}
constructor TPerson.Create(name: string; age: Integer);
begin
Self.name := name;
Self.age := age;
end;
constructor TPriorityQueue<T>.Create(const Comparison: TComparison<T>);
begin
inherited Create;
list := TList<T>.Create(TComparer<T>.Construct(Comparison));
end;
destructor TPriorityQueue<T>.Destroy;
begin
list.Free;
inherited;
end;
function TPriorityQueue<T>.Dequeue: T;
begin
Result := list.First;
list.Delete(0);
end;
procedure TPriorityQueue<T>.Enqueue(item: T);
begin
list.Add(item);
list.Sort;
end;
function TPriorityQueue<T>.Count: Integer;
begin
Result := list.Count;
end;
procedure TForm3.btn1Click(Sender: TObject);
var
pque: TPriorityQueue<TPerson>;
person: TPerson;
begin
pque := TPriorityQueue<TPerson>.Create(
function(const Left, Right: TPerson): Integer
begin
Result := Left.age - Right.age;
end);
pque.Enqueue(TPerson.Create('小李1', 1));
pque.Enqueue(TPerson.Create('小李3', 3));
pque.Enqueue(TPerson.Create('小李2', 2));
while pque.Count > 0 do
begin
person := pque.Dequeue;
mmo1.Lines.Add(person.name);
person.Free;
end;
pque.Free;
end;
procedure TForm3.FormCreate(Sender: TObject);
begin
ReportMemoryLeaksOnShutdown := True;
end;
end.
