unit Unit1;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.Grids, Vcl.StdCtrls, ClipBrd, Vcl.Menus,
  Vcl.Samples.Spin;

type
  TForm1 = class(TForm)
    StringGridOfArray: TStringGrid;
    Label1: TLabel;
    Label2: TLabel;
    Label3: TLabel;
    Label4: TLabel;
    StringGridOfIndex: TStringGrid;
    FindPalindromButton: TButton;
    SpinEditOfSizeArray: TSpinEdit;
    MainMenu: TMainMenu;
    FileButton: TMenuItem;
    OpenFileButton: TMenuItem;
    SaveFileButton: TMenuItem;
    OpenDialog: TOpenDialog;
    SaveDialog: TSaveDialog;
    LabelOfResult: TLabel;
    procedure FindPalindromButtonClick(Sender: TObject);
    procedure FormActivate(Sender: TObject);
    procedure StringGridOfArrayKeyPress(Sender: TObject; var Key: Char);
    procedure SpinEditOfSizeArrayChange(Sender: TObject);
    procedure OpenFileButtonClick(Sender: TObject);
    procedure SaveFileButtonClick(Sender: TObject);
    procedure FormCloseQuery(Sender: TObject; var CanClose: Boolean);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

function IsArrayCorrect(StringGrid: TStringGrid; MaxValue: TSpinEdit):Boolean;
var
    IsCorrect, VseOK: Boolean;
    I: Integer;
begin
    IsCorrect := True;
    I := 0;
    while ((I < MaxValue.Value) and (IsCorrect)) do
    begin
        try
            StrToInt(StringGrid.Cells[I, 0]);
        except
            IsCorrect := False;
        end;
        if IsCorrect then
            if not((StrToInt(StringGrid.Cells[I, 0]) < 2000000000) and (StrToInt(StringGrid.Cells[I, 0]) > -2000000000)) then
                IsCorrect := False;
        Inc(I);
    end;
    IsArrayCorrect := IsCorrect;
end;

procedure SearchForPalindrom(StringGrid, StringGridOfIndex: TStringGrid; Size, RowCount, Col: Integer; ClientHeight: Integer; LabelOfResult: TLabel);
var
    Bufi, Bufj, J, I: Integer;
    IsPalindrom: Boolean;
begin
    Bufi := 0;
    Bufj := 0;
    J := 0;
    IsPalindrom := True;
    for I := 0 to Size-1 do
    Begin
        J := Size;
        if (StrToInt(StringGrid.Cells[I, 0]) = StrToInt(StringGrid.Cells[J, 0])) then
        Begin
            Bufi := I;
            Bufj := J;
            IsPalindrom := True;
            while ((Bufi <> Bufj) and (IsPalindrom)) do
            Begin
                if ((Bufi = I) and (BufJ = J) and (Bufi+1 = BufJ) and (StrToInt(StringGrid.Cells[Bufi+1, 0]) = StrToInt(StringGrid.Cells[Bufj, 0]))) then
                    IsPalindrom := False;
                if (IsPalindrom and (StrToInt(StringGrid.Cells[Bufi, 0]) <> StrToInt(StringGrid.Cells[Bufj, 0]))) then
                    IsPalindrom := False;
                Inc(Bufi);
                Dec(Bufj);
            End;
            if ((IsPalindrom) and (I <> J)) then
            Begin
                StringGridOfIndex.Cells[0, Col] := IntToStr(I+1);
                StringGridOfIndex.Cells[1, Col] := IntToStr(J+1);
                StringGridOfIndex.Visible  := True;
                StringGridOfIndex.RowCount := RowCount;
                StringGridOfIndex.Height := 37 * StringGridOfIndex.RowCount;
                if (StringGridOfIndex.Height + StringGridOfIndex.Top < 100) then
                    ClientHeight := 100
                else
                    ClientHeight := StringGridOfIndex.Height + StringGridOfIndex.Top + 10;
                Inc(RowCount);
                Inc(Col);
            End;
        End;
    End;
    if (J > 0) then
        SearchForPalindrom(StringGrid, StringGridOfIndex, Size - 1, RowCount, Col, ClientHeight, LabelOfResult)
    else
        if not(StringGridOfIndex.Visible) then
            LabelOfResult.Visible := True;

end;

procedure TForm1.FindPalindromButtonClick(Sender : TObject);
var
    I, Size, RowCount, Col: Integer;
    Buf: String;
    IsCorrect: Boolean;
begin
    RowCount := 1;
    Col := 0;
    Size := SpinEditOfSizeArray.Value;
    if IsArrayCorrect(StringGridOfArray, SpinEditOfSizeArray) then
    begin
        SearchForPalindrom(StringGridOfArray, StringGridOfIndex, Size-1, RowCount, Col, ClientHeight, LabelOfResult);
        SaveFileButton.Enabled := True;
    end
    else
    begin
        MessageDlg('Проверьте введённые данные! Это должны быть целые числа в диапазоне +- 2*10^9', mtError, [mbOk], 0);
        SaveFileButton.Enabled := False;
    end;
end;

procedure TForm1.FormActivate(Sender: TObject);
begin
    SaveFileButton.Enabled := False;
    SpinEditOfSizeArray.Value := 3;
    Label1.Caption := 'Дана последовательность натуральных чисел а1, а2, …, аn. Разработать рекурсивную' +#13#10 + 'процедуру нахождения i и j, таких что подпоследовательность аi, аi+1, …, аj является перевертышем.';
end;

procedure TForm1.FormCloseQuery(Sender: TObject; var CanClose: Boolean);
var
    Choise: Integer;
begin
    Choise := Messagedlg('Вы уверены, что хотите выйти?', mtinformation, [mbYes, mbNo], 0);
    case Choise of
        mrYes: CanClose:= True;
        mrNo: CanClose:= False;
    end;
end;

function IsFileCorrect(Path: String): boolean;
var
    I, Value: Integer;
    IsCorrect: Boolean;
    UserFile: TextFile;
    Size: Integer;
begin
    AssignFile(UserFile, Path);
    Reset(UserFile);
    IsCorrect := True;
    I := 0;
    Try
        Readln(UserFile, Size);
    except
        IsCorrect := False;
    End;
    while not(SeekEoLn(UserFile)) and IsCorrect do
    Begin
        Try
            Read(UserFile, Value);
        except
            IsCorrect := False;
        End;
        Inc(I);
    End;

    if I<>Size then
        IsCorrect := False;

    CloseFile(UserFile);
    IsFileCorrect := IsCorrect;
end;

procedure TForm1.OpenFileButtonClick(Sender: TObject);
var
    I,Value, Size: Integer;
    UserFile: TextFile;
    Path: String;
begin
    if OpenDialog.Execute then
    Begin
        Path := OpenDialog.FileName;
        if IsFileCorrect(Path) then
        begin
            AssignFile(UserFile, OpenDialog.FileName);
            Reset(UserFile);
            Readln(UserFile, Size);
            SpinEditOfSizeArray.Value := Size;
            for I := 0 to SpinEditOfSizeArray.Value-1 do
                Begin
                    Read(UserFile, Value);
                    StringGridOfArray.Cells[i, 0] := IntToStr(Value);
                End;
            CloseFile(UserFile)
        end
        else
            MessageDlg('Ошибка. Проверьте данные в файле.', mtError, [mbOK], 0)
    End;
    if Length(StringGridOfArray.Cells[0,0]) > 0 then
        FindPalindromButton.Enabled := True;
end;

procedure TForm1.SaveFileButtonClick(Sender: TObject);
var
    SaveFile: TextFile;
    I: Integer;
begin
    if SaveDialog.Execute then
    Begin
        AssignFile(SaveFile, SaveDialog.FileName);
        Rewrite(SaveFile);
        Write(SaveFile, 'Для массива чисел: ');
        for I := 0 to SpinEditOfSizeArray.Value-1 do
            Write(SaveFile, StringGridOfArray.Cells[i, 0], ' ');
        Writeln(SaveFile);
        Writeln(SaveFile, 'Индексы элементов, которые являются крайними в подпоследовательности перевёртышей: ');
        if (StringGridOfIndex.Visible) then
        for I := 0 to SpinEditOfSizeArray.Value-1 do
        begin
            Write(SaveFile, StringGridOfIndex.Cells[0, I], ' ', StringGridOfIndex.Cells[1, I]);
            Writeln(SaveFile, StringGridOfIndex.Cells[0, I], ' ', StringGridOfIndex.Cells[1, I])
        end
        else
            Write(SaveFile, 'Отсутствуют!');
        CloseFile(SaveFile)
    End;
end;

procedure TForm1.SpinEditOfSizeArrayChange(Sender: TObject);
var
    I: Integer;
begin
    SaveFileButton.Enabled := False;
    LabelOfResult.Visible := False;
    StringGridOfIndex.Visible := False;
    StringGridOfIndex.Cells[0, 0] := '';
    StringGridOfIndex.Cells[1, 0] := '';
    StringGridOfIndex.RowCount := 1;
    if ((SpinEditOfSizeArray.Value > 2) and (SpinEditOfSizeArray.Value < 18)) then
    begin
        StringGridOfArray.Options := StringGridOfArray.Options+[goEditing];
        FindPalindromButton.Enabled := True;
    end
    else
    begin
        StringGridOfArray.Options := StringGridOfArray.Options-[goEditing];
        FindPalindromButton.Enabled := False;
    end;

    if (SpinEditOfSizeArray.Value < 18) then
    begin
        StringGridOfArray.ColCount := SpinEditOfSizeArray.Value;
        StringGridOfArray.Width := 85 * StringGridOfArray.ColCount;
        if (StringGridOfArray.Width + StringGridOfArray.Left < 682) then
            ClientWidth := 682
        else
            ClientWidth := StringGridOfArray.Width + StringGridOfArray.Left + 10;
    end;
end;

procedure TForm1.StringGridOfArrayKeyPress(Sender: TObject; var Key: Char);
begin
    FindPalindromButton.Enabled := True;
    if not(Key in ['0'..'9', '-', #8]) then
        Key :=#0;
end;

end.