Added solution for "Day 10: Pipe Maze", part 2
This commit is contained in:
Stefan Müller
parent
ac81b20db5
commit
344be871db
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@ -22,24 +22,52 @@ unit UPipeMaze;
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interface
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uses
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Classes, SysUtils, USolver;
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Classes, SysUtils, Generics.Collections, USolver;
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const
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CStartChar = 'S';
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type
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TDirection = (drEast, drSouth, drWest, drNorth);
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TPointArray = array of TPoint;
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{ TStepMapping }
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TStepMapping = class
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private
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FStartDirection, FNewDirection: TPoint;
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FMapChar: Char;
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FLeftSide, FRightSide: TPointArray;
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public
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property StartDirection: TPoint read FStartDirection;
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property NewDirection: TPoint read FNewDirection;
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property LeftSide: TPointArray read FLeftSide;
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property RightSide: TPointArray read FRightSide;
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constructor Create(const AStartDirection, ANewDirection: TPoint; const AMapChar: Char; const ALeftSide,
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ARightSide: TPointArray);
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constructor CreateReverse(constref AOriginal: TStepMapping);
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function TryStep(const AStartDirection: TPoint; const AMapChar: Char): Boolean;
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end;
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TStepMappings = specialize TObjectList<TStepMapping>;
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{ TPipeMaze }
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TPipeMaze = class(TSolver)
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private
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FWidth, FHeight: Integer;
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FStrings: TStringList;
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FStepMappings: TStepMappings;
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FMap, FEnclosureMap: TStringList;
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procedure InitStepMappings;
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procedure ParseMaze;
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function FindStart: TPoint;
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procedure DoFirstStep(var APosition: TPoint; out OStartDirection: TDirection);
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procedure DoStep(var APosition: TPoint; var ADirection: TDirection);
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procedure DoFirstStep(var APosition: TPoint; out OStartDirection: TPoint);
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procedure DoStep(var APosition: TPoint; var ADirection: TPoint);
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procedure CountEnclosureInside;
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function TryCountEnclosureSide(const AChar: Char; out OCount: Int64): Boolean;
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procedure UpdateEnclosureMap(const APosition: TPoint; constref AStepMapping: TStepMapping);
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function CheckMapBounds(const APosition: TPoint): Boolean;
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function GetMapChar(const APosition: TPoint): Char;
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function GetEnclosureMapChar(const APosition: TPoint): Char;
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procedure SetEnclosureMapChar(const APosition: TPoint; const AChar: Char);
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public
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constructor Create;
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destructor Destroy; override;
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@ -51,15 +79,68 @@ type
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implementation
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{ TStepMapping }
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constructor TStepMapping.Create(const AStartDirection, ANewDirection: TPoint; const AMapChar: Char; const ALeftSide,
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ARightSide: TPointArray);
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begin
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FStartDirection := AStartDirection;
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FNewDirection := ANewDirection;
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FMapChar := AMapChar;
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FLeftSide := ALeftSide;
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FRightSide := ARightSide;
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end;
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constructor TStepMapping.CreateReverse(constref AOriginal: TStepMapping);
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begin
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FStartDirection := Point(-AOriginal.FNewDirection.X, -AOriginal.FNewDirection.Y);
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FNewDirection := Point(-AOriginal.FStartDirection.X, -AOriginal.FStartDirection.Y);
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FMapChar := AOriginal.FMapChar;
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FLeftSide := AOriginal.FRightSide;
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FRightSide := AOriginal.FLeftSide;
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end;
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function TStepMapping.TryStep(const AStartDirection: TPoint; const AMapChar: Char): Boolean;
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begin
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Result := (FStartDirection = AStartDirection) and (FMapChar = AMapChar);
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end;
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{ TPipeMaze }
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procedure TPipeMaze.InitStepMappings;
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var
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i: Integer;
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begin
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FStepMappings.Add(TStepMapping.Create(Point(0, 1), Point(0, 1), '|',
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TPointArray.Create(Point(1, 0)),
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TPointArray.Create(Point(-1, 0))));
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FStepMappings.Add(TStepMapping.Create(Point(1, 0), Point(1, 0), '-',
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TPointArray.Create(Point(0, -1)),
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TPointArray.Create(Point(0, 1))));
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FStepMappings.Add(TStepMapping.Create(Point(-1, 0), Point(0, -1), 'L',
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TPointArray.Create(Point(0, 1), Point(-1, 1), Point(-1, 0)),
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[]));
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FStepMappings.Add(TStepMapping.Create(Point(0, 1), Point(-1, 0), 'J',
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TPointArray.Create(Point(1, 0), Point(1, 1), Point(0, 1)),
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[]));
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FStepMappings.Add(TStepMapping.Create(Point(1, 0), Point(0, 1), '7',
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TPointArray.Create(Point(0, -1), Point(1, -1), Point(1, 0)),
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[]));
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FStepMappings.Add(TStepMapping.Create(Point(0, -1), Point(1, 0), 'F',
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TPointArray.Create(Point(-1, 0), Point(-1, -1), Point(0, -1)),
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[]));
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// Adds reverse step mappings.
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for i := 0 to FStepMappings.Count - 1 do
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FStepMappings.Add(TStepMapping.CreateReverse(FStepMappings[i]));
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end;
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procedure TPipeMaze.ParseMaze;
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var
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start, current: TPoint;
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nextDirection: TDirection;
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start, current, nextDirection: TPoint;
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begin
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FHeight := FStrings.Count;
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FWidth := Length(FStrings[0]);
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FEnclosureMap := TStringList.Create;
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FEnclosureMap.AddStrings(FMap);
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start := FindStart;
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current := start;
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@ -73,6 +154,9 @@ begin
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DoStep(current, nextDirection);
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Inc(FPart1);
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until current = start;
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CountEnclosureInside;
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FEnclosureMap.Free;
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end;
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function TPipeMaze.FindStart: TPoint;
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@ -82,12 +166,12 @@ var
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begin
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foundStart := False;
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i := 0;
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while not foundStart and (i < FStrings.Count) do
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while not foundStart and (i < FMap.Count) do
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begin
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j := 1;
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while not foundStart and (j <= Length(FStrings[i])) do
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while not foundStart and (j <= Length(FMap[i])) do
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begin
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if FStrings[i][j] = CStartChar then
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if FMap[i][j] = CStartChar then
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begin
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foundStart := True;
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Result.X := j;
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@ -99,126 +183,171 @@ begin
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end;
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end;
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procedure TPipeMaze.DoFirstStep(var APosition: TPoint; out OStartDirection: TDirection);
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procedure TPipeMaze.DoFirstStep(var APosition: TPoint; out OStartDirection: TPoint);
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var
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stepMapping: TStepMapping;
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step: TPoint;
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begin
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// Checks going East.
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if APosition.X < FWidth then
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for stepMapping in FStepMappings do
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begin
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if FStrings[APosition.Y][APosition.X + 1] = '-' then
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step := APosition + stepMapping.StartDirection;
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if CheckMapBounds(step) and stepMapping.TryStep(stepMapping.StartDirection, GetMapChar(step)) then
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begin
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Inc(APosition.X);
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OStartDirection := drEast;
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Exit;
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end
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else if FStrings[APosition.Y][APosition.X + 1] = 'J' then
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begin
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Inc(APosition.X);
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OStartDirection := drNorth;
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Exit;
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end
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else if FStrings[APosition.Y][APosition.X + 1] = '7' then
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begin
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Inc(APosition.X);
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OStartDirection := drSouth;
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Exit;
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end;
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end;
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UpdateEnclosureMap(APosition, stepMapping);
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UpdateEnclosureMap(step, stepMapping);
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// Checks going South.
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if APosition.Y < FHeight - 1 then
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begin
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if FStrings[APosition.Y + 1][APosition.X] = '|' then
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begin
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Inc(APosition.Y);
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OStartDirection := drSouth;
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Exit;
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end
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else if FStrings[APosition.Y + 1][APosition.X] = 'L' then
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begin
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Inc(APosition.Y);
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OStartDirection := drEast;
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Exit;
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end
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else if FStrings[APosition.Y + 1][APosition.X] = 'J' then
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begin
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Inc(APosition.Y);
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OStartDirection := drWest;
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Exit;
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end;
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end;
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// Checks going West.
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if APosition.X > 1 then
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begin
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if FStrings[APosition.Y][APosition.X - 1] = '-' then
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begin
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Dec(APosition.X);
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OStartDirection := drWest;
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Exit;
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end
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else if FStrings[APosition.Y][APosition.X - 1] = 'L' then
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begin
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Dec(APosition.X);
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OStartDirection := drNorth;
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Exit;
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end
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else if FStrings[APosition.Y][APosition.X - 1] = 'F' then
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begin
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Dec(APosition.X);
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OStartDirection := drSouth;
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APosition := step;
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OStartDirection := stepMapping.NewDirection;
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Exit;
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end;
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end;
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end;
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procedure TPipeMaze.DoStep(var APosition: TPoint; var ADirection: TDirection);
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procedure TPipeMaze.DoStep(var APosition: TPoint; var ADirection: TPoint);
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var
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stepMapping: TStepMapping;
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begin
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case ADirection of
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drEast: begin
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Inc(APosition.X);
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case FStrings[APosition.Y][APosition.X] of
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'J': ADirection := drNorth;
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'7': ADirection := drSouth;
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end;
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end;
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drSouth: begin
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Inc(APosition.Y);
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case FStrings[APosition.Y][APosition.X] of
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'L': ADirection := drEast;
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'J': ADirection := drWest;
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end;
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end;
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drWest: begin
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Dec(APosition.X);
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case FStrings[APosition.Y][APosition.X] of
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'L': ADirection := drNorth;
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'F': ADirection := drSouth;
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end;
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end;
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drNorth: begin
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Dec(APosition.Y);
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case FStrings[APosition.Y][APosition.X] of
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'7': ADirection := drWest;
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'F': ADirection := drEast;
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APosition := APosition + ADirection;
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for stepMapping in FStepMappings do
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begin
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if stepMapping.TryStep(ADirection, GetMapChar(APosition)) then
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begin
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ADirection := stepMapping.NewDirection;
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UpdateEnclosureMap(APosition, stepMapping);
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Exit;
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end;
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end;
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end;
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procedure TPipeMaze.CountEnclosureInside;
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begin
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if not TryCountEnclosureSide('l', FPart2) then
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TryCountEnclosureSide('r', FPart2);
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end;
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function TPipeMaze.TryCountEnclosureSide(const AChar: Char; out OCount: Int64): Boolean;
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var
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directions: TPointArray;
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stack: specialize TStack<TPoint>;
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i, j: Integer;
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position, direction, neighbor: TPoint;
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c: Char;
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begin
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directions := TPointArray.Create(Point(0, -1), Point(-1, 0), Point(0, 1), Point(1, 0));
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stack := specialize TStack<TPoint>.Create;
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OCount := 0;
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Result := True;
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for i := 0 to FEnclosureMap.Count - 1 do
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begin
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for j := 1 to Length(FEnclosureMap[i]) do
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begin
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position := Point(j, i);
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if GetEnclosureMapChar(position) = AChar then
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begin
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stack.Push(position);
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SetEnclosureMapChar(position, '%');
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Inc(OCount);
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end;
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while stack.Count > 0 do
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begin
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position := stack.Pop;
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for direction in directions do
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begin
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if CheckMapBounds(position + direction) then
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begin
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// Checks the neighboring position.
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neighbor := position + direction;
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c := GetEnclosureMapChar(neighbor);
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if (c <> '%') and (c <> '#') then
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begin
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stack.Push(neighbor);
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SetEnclosureMapChar(neighbor, '%');
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Inc(OCount);
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end;
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end else
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begin
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// Exits after hitting an edge of the map.
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Result := False;
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stack.Free;
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Exit;
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end;
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end;
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end;
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end;
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end;
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stack.Free;
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end;
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procedure TPipeMaze.UpdateEnclosureMap(const APosition: TPoint; constref AStepMapping: TStepMapping);
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var
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offset, sidePosition: TPoint;
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side: TPointArray;
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c: Char;
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i: Integer;
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begin
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SetEnclosureMapChar(APosition, '#');
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side := AStepMapping.LeftSide;
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c := 'l';
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for i := 1 to 2 do
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begin
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for offset in side do
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begin
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sidePosition := APosition + offset;
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if CheckMapBounds(sidePosition) and (GetEnclosureMapChar(sidePosition) <> '#') then
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SetEnclosureMapChar(sidePosition, c);
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end;
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side := AStepMapping.RightSide;
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c := 'r';
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end;
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end;
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function TPipeMaze.CheckMapBounds(const APosition: TPoint): Boolean;
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begin
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Result := (0 <= APosition.Y) and (APosition.Y < FMap.Count)
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and (0 < APosition.X) and (APosition.X <= Length(FMap[0]));
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end;
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function TPipeMaze.GetMapChar(const APosition: TPoint): Char;
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begin
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Result := FMap[APosition.Y][APosition.X];
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end;
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function TPipeMaze.GetEnclosureMapChar(const APosition: TPoint): Char;
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begin
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Result := FEnclosureMap[APosition.Y][APosition.X];
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end;
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procedure TPipeMaze.SetEnclosureMapChar(const APosition: TPoint; const AChar: Char);
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var
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s: string;
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begin
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s := FEnclosureMap[APosition.Y];
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s[APosition.X] := AChar;
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FEnclosureMap[APosition.Y] := s;
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end;
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constructor TPipeMaze.Create;
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begin
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FStrings := TStringList.Create;
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FStepMappings := TStepMappings.Create;
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InitStepMappings;
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FMap := TStringList.Create;
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end;
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destructor TPipeMaze.Destroy;
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begin
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FStrings.Free;
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FStepMappings.Free;
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FMap.Free;
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inherited Destroy;
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end;
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procedure TPipeMaze.ProcessDataLine(const ALine: string);
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begin
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FStrings.Add(ALine);
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FMap.Add(ALine);
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end;
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procedure TPipeMaze.Finish;
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@ -90,6 +90,66 @@ type
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procedure TestPart1;
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end;
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{ TExample5PipeMaze }
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TExample5PipeMaze = class(TPipeMaze)
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function GetDataFileName: string; override;
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end;
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{ TPipeMazeExample5TestCase }
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TPipeMazeExample5TestCase = class(TExampleEngineBaseTest)
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protected
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function CreateSolver: ISolver; override;
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published
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procedure TestPart2;
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end;
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{ TExample6PipeMaze }
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TExample6PipeMaze = class(TPipeMaze)
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function GetDataFileName: string; override;
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end;
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{ TPipeMazeExample6TestCase }
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TPipeMazeExample6TestCase = class(TExampleEngineBaseTest)
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protected
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function CreateSolver: ISolver; override;
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published
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procedure TestPart2;
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end;
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{ TExample7PipeMaze }
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TExample7PipeMaze = class(TPipeMaze)
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function GetDataFileName: string; override;
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end;
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{ TPipeMazeExample7TestCase }
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TPipeMazeExample7TestCase = class(TExampleEngineBaseTest)
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protected
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function CreateSolver: ISolver; override;
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published
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procedure TestPart2;
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end;
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{ TExample8PipeMaze }
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TExample8PipeMaze = class(TPipeMaze)
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function GetDataFileName: string; override;
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end;
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{ TPipeMazeExample8TestCase }
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TPipeMazeExample8TestCase = class(TExampleEngineBaseTest)
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protected
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function CreateSolver: ISolver; override;
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published
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procedure TestPart2;
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end;
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implementation
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{ TPipeMazeFullDataTestCase }
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@ -106,7 +166,7 @@ end;
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procedure TPipeMazeFullDataTestCase.TestPart2;
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begin
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AssertEquals(-1, FSolver.GetResultPart2);
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AssertEquals(355, FSolver.GetResultPart2);
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end;
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{ TPipeMazeExampleTestCase }
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@ -178,6 +238,82 @@ begin
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AssertEquals(8, FSolver.GetResultPart1);
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end;
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{ TExample5PipeMaze }
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function TExample5PipeMaze.GetDataFileName: string;
|
||||
begin
|
||||
Result := 'pipe_maze5.txt';
|
||||
end;
|
||||
|
||||
{ TPipeMazeExample5TestCase }
|
||||
|
||||
function TPipeMazeExample5TestCase.CreateSolver: ISolver;
|
||||
begin
|
||||
Result := TExample5PipeMaze.Create;
|
||||
end;
|
||||
|
||||
procedure TPipeMazeExample5TestCase.TestPart2;
|
||||
begin
|
||||
AssertEquals(4, FSolver.GetResultPart2);
|
||||
end;
|
||||
|
||||
{ TExample6PipeMaze }
|
||||
|
||||
function TExample6PipeMaze.GetDataFileName: string;
|
||||
begin
|
||||
Result := 'pipe_maze6.txt';
|
||||
end;
|
||||
|
||||
{ TPipeMazeExample6TestCase }
|
||||
|
||||
function TPipeMazeExample6TestCase.CreateSolver: ISolver;
|
||||
begin
|
||||
Result := TExample6PipeMaze.Create;
|
||||
end;
|
||||
|
||||
procedure TPipeMazeExample6TestCase.TestPart2;
|
||||
begin
|
||||
AssertEquals(4, FSolver.GetResultPart2);
|
||||
end;
|
||||
|
||||
{ TExample7PipeMaze }
|
||||
|
||||
function TExample7PipeMaze.GetDataFileName: string;
|
||||
begin
|
||||
Result := 'pipe_maze7.txt';
|
||||
end;
|
||||
|
||||
{ TPipeMazeExample7TestCase }
|
||||
|
||||
function TPipeMazeExample7TestCase.CreateSolver: ISolver;
|
||||
begin
|
||||
Result := TExample7PipeMaze.Create;
|
||||
end;
|
||||
|
||||
procedure TPipeMazeExample7TestCase.TestPart2;
|
||||
begin
|
||||
AssertEquals(8, FSolver.GetResultPart2);
|
||||
end;
|
||||
|
||||
{ TExample8PipeMaze }
|
||||
|
||||
function TExample8PipeMaze.GetDataFileName: string;
|
||||
begin
|
||||
Result := 'pipe_maze8.txt';
|
||||
end;
|
||||
|
||||
{ TPipeMazeExample8TestCase }
|
||||
|
||||
function TPipeMazeExample8TestCase.CreateSolver: ISolver;
|
||||
begin
|
||||
Result := TExample8PipeMaze.Create;
|
||||
end;
|
||||
|
||||
procedure TPipeMazeExample8TestCase.TestPart2;
|
||||
begin
|
||||
AssertEquals(10, FSolver.GetResultPart2);
|
||||
end;
|
||||
|
||||
initialization
|
||||
|
||||
RegisterTest(TPipeMazeFullDataTestCase);
|
||||
|
|
@ -185,4 +321,8 @@ initialization
|
|||
RegisterTest(TPipeMazeExample2TestCase);
|
||||
RegisterTest(TPipeMazeExample3TestCase);
|
||||
RegisterTest(TPipeMazeExample4TestCase);
|
||||
RegisterTest(TPipeMazeExample5TestCase);
|
||||
RegisterTest(TPipeMazeExample6TestCase);
|
||||
RegisterTest(TPipeMazeExample7TestCase);
|
||||
RegisterTest(TPipeMazeExample8TestCase);
|
||||
end.
|
||||
|
|
|
|||
Loading…
Reference in New Issue