Added solution for "Day 10: Pipe Maze", part 1

AdventOfCode.lpi

@@ -73,6 +73,10 @@
         <Filename Value="solvers\UMirageMaintenance.pas"/>
         <IsPartOfProject Value="True"/>
       </Unit>
+      <Unit>
+        <Filename Value="solvers\UPipeMaze.pas"/>
+        <IsPartOfProject Value="True"/>
+      </Unit>
     </Units>
   </ProjectOptions>
   <CompilerOptions>

AdventOfCode.lpr

@@ -26,7 +26,7 @@ uses
   Classes, SysUtils, CustApp,
   USolver,
   UTrebuchet, UCubeConundrum, UGearRatios, UScratchcards, UGiveSeedFertilizer, UWaitForIt, UCamelCards,
-  UHauntedWasteland, UNumberTheory, UMirageMaintenance;
+  UHauntedWasteland, UNumberTheory, UMirageMaintenance, UPipeMaze;
 
 type
 
@@ -60,6 +60,7 @@ begin
   engine.RunAndFree(TCamelCards.Create);
   engine.RunAndFree(THauntedWasteland.Create);
   engine.RunAndFree(TMirageMaintenance.Create);
+  engine.RunAndFree(TPipeMaze.Create);
   engine.Free;
 end;
 

solvers/UPipeMaze.pas

@@ -0,0 +1,240 @@
+{
+  Solutions to the Advent Of Code.
+  Copyright (C) 2023  Stefan Müller
+
+  This program is free software: you can redistribute it and/or modify it under
+  the terms of the GNU General Public License as published by the Free Software
+  Foundation, either version 3 of the License, or (at your option) any later
+  version.
+
+  This program is distributed in the hope that it will be useful, but WITHOUT
+  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+  FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License along with
+  this program.  If not, see <http://www.gnu.org/licenses/>.
+}
+
+unit UPipeMaze;
+
+{$mode ObjFPC}{$H+}
+
+interface
+
+uses
+  Classes, SysUtils, USolver;
+
+const
+  CStartChar = 'S';
+
+type
+  TDirection = (drEast, drSouth, drWest, drNorth);
+
+  { TPipeMaze }
+
+  TPipeMaze = class(TSolver)
+  private
+    FWidth, FHeight: Integer;
+    FStrings: TStringList;
+    procedure ParseMaze;
+    function FindStart: TPoint;
+    procedure DoFirstStep(var APosition: TPoint; out OStartDirection: TDirection);
+    procedure DoStep(var APosition: TPoint; var ADirection: TDirection);
+  public
+    constructor Create;
+    destructor Destroy; override;
+    procedure ProcessDataLine(const ALine: string); override;
+    procedure Finish; override;
+    function GetDataFileName: string; override;
+    function GetPuzzleName: string; override;
+  end;
+
+implementation
+
+{ TPipeMaze }
+
+procedure TPipeMaze.ParseMaze;
+var
+  start, current: TPoint;
+  nextDirection: TDirection;
+begin
+  FHeight := FStrings.Count;
+  FWidth := Length(FStrings[0]);
+
+  start := FindStart;
+  current := start;
+
+  DoFirstStep(current, nextDirection);
+  DoStep(current, nextDirection);
+  Inc(FPart1);
+
+  repeat
+    DoStep(current, nextDirection);
+    DoStep(current, nextDirection);
+    Inc(FPart1);
+  until current = start;
+end;
+
+function TPipeMaze.FindStart: TPoint;
+var
+  i, j: Integer;
+  foundStart: Boolean;
+begin
+  foundStart := False;
+  i := 0;
+  while not foundStart and (i < FStrings.Count) do
+  begin
+    j := 1;
+    while not foundStart and (j <= Length(FStrings[i])) do
+    begin
+      if FStrings[i][j] = CStartChar then
+      begin
+        foundStart := True;
+        Result.X := j;
+        Result.Y := i;
+      end;
+      Inc(j);
+    end;
+    Inc(i);
+  end;
+end;
+
+procedure TPipeMaze.DoFirstStep(var APosition: TPoint; out OStartDirection: TDirection);
+begin
+  // Checks going East.
+  if APosition.X < FWidth then
+  begin
+    if FStrings[APosition.Y][APosition.X + 1] = '-' then
+    begin
+      Inc(APosition.X);
+      OStartDirection := drEast;
+      Exit;
+    end
+    else if FStrings[APosition.Y][APosition.X + 1] = 'J' then
+    begin
+      Inc(APosition.X);
+      OStartDirection := drNorth;
+      Exit;
+    end
+    else if FStrings[APosition.Y][APosition.X + 1] = '7' then
+    begin
+      Inc(APosition.X);
+      OStartDirection := drSouth;
+      Exit;
+    end;
+  end;
+
+  // Checks going South.
+  if APosition.Y < FHeight - 1 then
+  begin
+    if FStrings[APosition.Y + 1][APosition.X] = '|' then
+    begin
+      Inc(APosition.Y);
+      OStartDirection := drSouth;
+      Exit;
+    end
+    else if FStrings[APosition.Y + 1][APosition.X] = 'L' then
+    begin
+      Inc(APosition.Y);
+      OStartDirection := drEast;
+      Exit;
+    end
+    else if FStrings[APosition.Y + 1][APosition.X] = 'J' then
+    begin
+      Inc(APosition.Y);
+      OStartDirection := drWest;
+      Exit;
+    end;
+  end;
+
+  // Checks going West.
+  if APosition.X > 1 then
+  begin
+    if FStrings[APosition.Y][APosition.X - 1] = '-' then
+    begin
+      Dec(APosition.X);
+      OStartDirection := drWest;
+      Exit;
+    end
+    else if FStrings[APosition.Y][APosition.X - 1] = 'L' then
+    begin
+      Dec(APosition.X);
+      OStartDirection := drNorth;
+      Exit;
+    end
+    else if FStrings[APosition.Y][APosition.X - 1] = 'F' then
+    begin
+      Dec(APosition.X);
+      OStartDirection := drSouth;
+      Exit;
+    end;
+  end;
+end;
+
+procedure TPipeMaze.DoStep(var APosition: TPoint; var ADirection: TDirection);
+begin
+  case ADirection of
+    drEast: begin
+      Inc(APosition.X);
+      case FStrings[APosition.Y][APosition.X] of
+        'J': ADirection := drNorth;
+        '7': ADirection := drSouth;
+      end;
+    end;
+    drSouth: begin
+      Inc(APosition.Y);
+      case FStrings[APosition.Y][APosition.X] of
+        'L': ADirection := drEast;
+        'J': ADirection := drWest;
+      end;
+    end;
+    drWest: begin
+      Dec(APosition.X);
+      case FStrings[APosition.Y][APosition.X] of
+        'L': ADirection := drNorth;
+        'F': ADirection := drSouth;
+      end;
+    end;
+    drNorth: begin
+      Dec(APosition.Y);
+      case FStrings[APosition.Y][APosition.X] of
+        '7': ADirection := drWest;
+        'F': ADirection := drEast;
+      end;
+    end;
+  end;
+end;
+
+constructor TPipeMaze.Create;
+begin
+  FStrings := TStringList.Create;
+end;
+
+destructor TPipeMaze.Destroy;
+begin
+  FStrings.Free;
+  inherited Destroy;
+end;
+
+procedure TPipeMaze.ProcessDataLine(const ALine: string);
+begin
+  FStrings.Add(ALine);
+end;
+
+procedure TPipeMaze.Finish;
+begin
+  ParseMaze;
+end;
+
+function TPipeMaze.GetDataFileName: string;
+begin
+  Result := 'pipe_maze.txt';
+end;
+
+function TPipeMaze.GetPuzzleName: string;
+begin
+  Result := 'Day 10: Pipe Maze';
+end;
+
+end.
+

tests/AdventOfCodeFPCUnit.lpi

@@ -80,6 +80,10 @@
         <Filename Value="UMirageMaintenanceTestCases.pas"/>
         <IsPartOfProject Value="True"/>
       </Unit>
+      <Unit>
+        <Filename Value="UPipeMazeTestCases.pas"/>
+        <IsPartOfProject Value="True"/>
+      </Unit>
     </Units>
   </ProjectOptions>
   <CompilerOptions>

tests/AdventOfCodeFPCUnit.lpr

@@ -5,7 +5,7 @@ program AdventOfCodeFPCUnit;
 uses
   Interfaces, Forms, GuiTestRunner, USolver, UBaseTestCases, UTrebuchetTestCases, UCubeConundrumTestCases,
   UGearRatiosTestCases, UScratchcardsTestCases, UGiveSeedFertilizerTestCases, UWaitForItTestCases, UCamelCardsTestCases,
-  UHauntedWastelandTestCases, UMirageMaintenanceTestCases;
+  UHauntedWastelandTestCases, UMirageMaintenanceTestCases, UPipeMazeTestCases;
 
 {$R *.res}
 

tests/UPipeMazeTestCases.pas

@@ -0,0 +1,188 @@
+{
+  Solutions to the Advent Of Code.
+  Copyright (C) 2023  Stefan Müller
+
+  This program is free software: you can redistribute it and/or modify it under
+  the terms of the GNU General Public License as published by the Free Software
+  Foundation, either version 3 of the License, or (at your option) any later
+  version.
+
+  This program is distributed in the hope that it will be useful, but WITHOUT
+  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+  FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License along with
+  this program.  If not, see <http://www.gnu.org/licenses/>.
+}
+
+unit UPipeMazeTestCases;
+
+{$mode ObjFPC}{$H+}
+
+interface
+
+uses
+  Classes, SysUtils, fpcunit, testregistry, USolver, UBaseTestCases, UPipeMaze;
+
+type
+
+  { TPipeMazeFullDataTestCase }
+
+  TPipeMazeFullDataTestCase = class(TEngineBaseTest)
+  protected
+    function CreateSolver: ISolver; override;
+  published
+    procedure TestPart1;
+    procedure TestPart2;
+  end;
+
+  { TPipeMazeExampleTestCase }
+
+  TPipeMazeExampleTestCase = class(TExampleEngineBaseTest)
+  protected
+    function CreateSolver: ISolver; override;
+  published
+    procedure TestPart1;
+  end;
+
+  { TExample2PipeMaze }
+
+  TExample2PipeMaze = class(TPipeMaze)
+    function GetDataFileName: string; override;
+  end;
+
+  { TPipeMazeExample2TestCase }
+
+  TPipeMazeExample2TestCase = class(TExampleEngineBaseTest)
+  protected
+    function CreateSolver: ISolver; override;
+  published
+    procedure TestPart1;
+  end;
+
+  { TExample3PipeMaze }
+
+  TExample3PipeMaze = class(TPipeMaze)
+    function GetDataFileName: string; override;
+  end;
+
+  { TPipeMazeExample3TestCase }
+
+  TPipeMazeExample3TestCase = class(TExampleEngineBaseTest)
+  protected
+    function CreateSolver: ISolver; override;
+  published
+    procedure TestPart1;
+  end;
+
+  { TExample4PipeMaze }
+
+  TExample4PipeMaze = class(TPipeMaze)
+    function GetDataFileName: string; override;
+  end;
+
+  { TPipeMazeExample4TestCase }
+
+  TPipeMazeExample4TestCase = class(TExampleEngineBaseTest)
+  protected
+    function CreateSolver: ISolver; override;
+  published
+    procedure TestPart1;
+  end;
+
+implementation
+
+{ TPipeMazeFullDataTestCase }
+
+function TPipeMazeFullDataTestCase.CreateSolver: ISolver;
+begin
+  Result := TPipeMaze.Create;
+end;
+
+procedure TPipeMazeFullDataTestCase.TestPart1;
+begin
+  AssertEquals(7097, FSolver.GetResultPart1);
+end;
+
+procedure TPipeMazeFullDataTestCase.TestPart2;
+begin
+  AssertEquals(-1, FSolver.GetResultPart2);
+end;
+
+{ TPipeMazeExampleTestCase }
+
+function TPipeMazeExampleTestCase.CreateSolver: ISolver;
+begin
+  Result := TPipeMaze.Create;
+end;
+
+procedure TPipeMazeExampleTestCase.TestPart1;
+begin
+  AssertEquals(4, FSolver.GetResultPart1);
+end;
+
+{ TExample2PipeMaze }
+
+function TExample2PipeMaze.GetDataFileName: string;
+begin
+  Result := 'pipe_maze2.txt';
+end;
+
+{ TPipeMazeExample2TestCase }
+
+function TPipeMazeExample2TestCase.CreateSolver: ISolver;
+begin
+  Result := TExample2PipeMaze.Create;
+end;
+
+procedure TPipeMazeExample2TestCase.TestPart1;
+begin
+  AssertEquals(4, FSolver.GetResultPart1);
+end;
+
+{ TExample3PipeMaze }
+
+function TExample3PipeMaze.GetDataFileName: string;
+begin
+  Result := 'pipe_maze3.txt';
+end;
+
+{ TPipeMazeExample3TestCase }
+
+function TPipeMazeExample3TestCase.CreateSolver: ISolver;
+begin
+  Result := TExample3PipeMaze.Create;
+end;
+
+procedure TPipeMazeExample3TestCase.TestPart1;
+begin
+  AssertEquals(8, FSolver.GetResultPart1);
+end;
+
+{ TExample4PipeMaze }
+
+function TExample4PipeMaze.GetDataFileName: string;
+begin
+  Result := 'pipe_maze4.txt';
+end;
+
+{ TPipeMazeExample4TestCase }
+
+function TPipeMazeExample4TestCase.CreateSolver: ISolver;
+begin
+  Result := TExample4PipeMaze.Create;
+end;
+
+procedure TPipeMazeExample4TestCase.TestPart1;
+begin
+  AssertEquals(8, FSolver.GetResultPart1);
+end;
+
+initialization
+
+  RegisterTest(TPipeMazeFullDataTestCase);
+  RegisterTest(TPipeMazeExampleTestCase);
+  RegisterTest(TPipeMazeExample2TestCase);
+  RegisterTest(TPipeMazeExample3TestCase);
+  RegisterTest(TPipeMazeExample4TestCase);
+end.