Added solution for "Day 16: The Floor Will Be Lava", part 2
This commit is contained in:
Stefan Müller
parent
e9737f0265
commit
01ec0be32c
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@ -42,14 +42,27 @@ type
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EnergyChange: TEnergyState;
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end;
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{ TEnergyMap }
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TEnergyMap = class
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private
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FWidth, FHeight: Integer;
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FStates: array of array of TEnergyState;
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public
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constructor Create(const AWidth, AHeight: Integer);
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function IsBeamOutOfBounds(constref ABeam: TBeam): Boolean;
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function Energize(constref APosition: TPoint; const AChange: TEnergyState): Boolean;
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function CalcEnergizedTiles: Int64;
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end;
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{ TFloorWillBeLava }
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TFloorWillBeLava = class(TSolver)
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private
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FLines: TStringList;
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function IsBeamOutOfBounds(constref ABeam: TBeam; const AWidth, AHeight: Integer): Boolean;
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function GetTile(constref APosition: TPoint): Char;
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function GetNewBeam(constref APosition, ADirection: TPoint): TBeam;
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function ProcessBeam(ABeam: TBeam): Int64;
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public
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constructor Create;
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destructor Destroy; override;
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@ -62,7 +75,6 @@ type
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const
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CNoDirection: TPoint = (X: 0; Y: 0);
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CEmptyChar = '.';
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CStartingBeam: TBeam = (Position: (X: 0; Y: 0); Direction: (X: 1; Y: 0));
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CTransitions: array of TTransition = (
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(IncomingDirection: (X: 1; Y: 0); OutgoingDirection: (X: 0; Y: -1); SplitDirection: (X: 0; Y: 0); Tile: '/';
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EnergyChange: esWestOrHorizontal),
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@ -92,14 +104,58 @@ const
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implementation
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{ TFloorWillBeLava }
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{ TEnergyMap }
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function TFloorWillBeLava.IsBeamOutOfBounds(constref ABeam: TBeam; const AWidth, AHeight: Integer): Boolean;
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constructor TEnergyMap.Create(const AWidth, AHeight: Integer);
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var
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i, j: Integer;
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begin
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Result := (ABeam.Position.X < 0) or (ABeam.Position.X >= AWidth)
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or (ABeam.Position.Y < 0) or (ABeam.Position.Y >= AHeight);
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FWidth := AWidth;
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FHeight := AHeight;
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SetLength(FStates, FWidth, FHeight);
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for i := 0 to FWidth - 1 do
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for j := 0 to FHeight - 1 do
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FStates[i, j] := esNone;
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end;
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function TEnergyMap.IsBeamOutOfBounds(constref ABeam: TBeam): Boolean;
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begin
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Result := (ABeam.Position.X < 0) or (ABeam.Position.X >= FWidth)
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or (ABeam.Position.Y < 0) or (ABeam.Position.Y >= FHeight);
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end;
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function TEnergyMap.Energize(constref APosition: TPoint; const AChange: TEnergyState): Boolean;
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begin
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Result := False;
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case FStates[APosition.X, APosition.Y] of
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esNone: FStates[APosition.X, APosition.Y] := AChange;
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esWestOrHorizontal:
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if AChange = esEastOrVertical then
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FStates[APosition.X, APosition.Y] := esBoth
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else
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Result := True;
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esEastOrVertical:
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if AChange = esWestOrHorizontal then
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FStates[APosition.X, APosition.Y] := esBoth
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else
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Result := True;
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esBoth: Result := True;
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end;
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end;
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function TEnergyMap.CalcEnergizedTiles: Int64;
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var
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i, j: Integer;
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begin
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Result := 0;
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for i := 0 to FWidth - 1 do
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for j := 0 to FHeight - 1 do
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if FStates[i, j] <> esNone then
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Inc(Result);
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end;
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{ TFloorWillBeLava }
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function TFloorWillBeLava.GetTile(constref APosition: TPoint): Char;
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begin
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Result := FLines[APosition.Y][APosition.X + 1];
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@ -111,6 +167,62 @@ begin
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Result.Direction := ADirection;
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end;
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function TFloorWillBeLava.ProcessBeam(ABeam: TBeam): Int64;
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var
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done: Boolean;
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energyMap: TEnergyMap;
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stack: specialize TStack<TBeam>;
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transition: TTransition;
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energyChange: TEnergyState;
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begin
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done := False;
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energyMap := TEnergyMap.Create(Length(FLines[0]), FLines.Count);
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stack := specialize TStack<TBeam>.Create;
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repeat
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// Processes the current beam.
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if energyMap.IsBeamOutOfBounds(ABeam) then
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done := True
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else begin
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if ABeam.Direction.X <> 0 then
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energyChange := esWestOrHorizontal
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else
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energyChange := esEastOrVertical;
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if GetTile(ABeam.Position) <> CEmptyChar then
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begin
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// Checks the current position for direction changes and splits.
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for transition in CTransitions do
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if (transition.IncomingDirection = ABeam.Direction) and (transition.Tile = GetTile(ABeam.Position)) then
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begin
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if transition.SplitDirection <> CNoDirection then
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stack.Push(GetNewBeam(ABeam.Position + transition.SplitDirection, transition.SplitDirection));
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ABeam.Direction := transition.OutgoingDirection;
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energyChange := transition.EnergyChange;
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Break;
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end;
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end;
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done := energyMap.Energize(ABeam.Position, energyChange);
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// Moves the beam.
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ABeam.Position := ABeam.Position + ABeam.Direction;
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end;
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if done and (stack.Count > 0) then
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begin
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// Starts the next beam that was split earlier.
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done := False;
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ABeam := stack.Pop;
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end;
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until done;
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stack.Free;
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Result := energyMap.CalcEnergizedTiles;
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energyMap.Free;
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end;
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constructor TFloorWillBeLava.Create;
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begin
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FLines := TStringList.Create;
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@ -129,87 +241,30 @@ end;
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procedure TFloorWillBeLava.Finish;
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var
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energyMap: array of array of TEnergyState;
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width, height, i, j: Integer;
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done: Boolean;
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stack: specialize TStack<TBeam>;
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i, x, y, width, height: Integer;
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beam: TBeam;
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transition: TTransition;
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energyChange: TEnergyState;
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s: string;
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count: Int64;
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begin
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// Initializes energy map.
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width := Length(FLines[0]);
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height := FLines.Count;
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SetLength(energyMap, width, height);
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for i := 0 to width - 1 do
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for j := 0 to height - 1 do
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energyMap[i, j] := esNone;
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// Starts beam.
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done := False;
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beam := CStartingBeam;
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stack := specialize TStack<TBeam>.Create;
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repeat
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// Processes the current beam.
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if IsBeamOutOfBounds(beam, width, height) then
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done := True
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else begin
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if beam.Direction.X <> 0 then
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energyChange := esWestOrHorizontal
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else
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energyChange := esEastOrVertical;
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if GetTile(beam.Position) <> CEmptyChar then
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for y := 0 to 1 do
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for x := 0 to 1 do
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begin
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// Checks the current position for direction changes and splits.
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for transition in CTransitions do
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if (transition.IncomingDirection = beam.Direction) and (transition.Tile = GetTile(beam.Position)) then
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// Direction is horizontal for y = 0, and vertical for y = 1.
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// Direction is positive for x = 0, and negative for x = 1.
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beam.Direction := Point((1 - 2 * x) * (1 - y), (1 - 2 * x) * y);
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// Looping over the height for y = 0, and over the width for y = 1.
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for i := 0 to height - 1 + (width - height) * y do
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begin
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if transition.SplitDirection <> CNoDirection then
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stack.Push(GetNewBeam(beam.Position + transition.SplitDirection, transition.SplitDirection));
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beam.Direction := transition.OutgoingDirection;
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energyChange := transition.EnergyChange;
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Break;
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// Position is at left or top for x = 0, and right or bottom for x = 1.
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beam.Position := Point((x * (width - 1)) * (1 - y) + i * y, (x * (height - 1) - i) * y + i);
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count := ProcessBeam(beam);
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if FPart1 <= 0 then
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FPart1 := count;
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if FPart2 < count then
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FPart2 := count;
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end;
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end;
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// Energizes the current position.
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case energyMap[beam.Position.X, beam.Position.Y] of
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esNone: energyMap[beam.Position.X, beam.Position.Y] := energyChange;
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esWestOrHorizontal:
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if energyChange = esEastOrVertical then
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energyMap[beam.Position.X, beam.Position.Y] := esBoth
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else
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done := True;
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esEastOrVertical:
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if energyChange = esWestOrHorizontal then
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energyMap[beam.Position.X, beam.Position.Y] := esBoth
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else
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done := True;
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esBoth: done := True;
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end;
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// Moves the beam.
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beam.Position := beam.Position + beam.Direction;
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end;
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if done and (stack.Count > 0) then
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begin
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// Starts the next beam that was split earlier.
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done := False;
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beam := stack.Pop;
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end;
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until done;
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stack.Free;
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// Counts energized tiles.
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for i := 0 to width - 1 do
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for j := 0 to height - 1 do
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if energyMap[i, j] <> esNone then
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Inc(FPart1);
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end;
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function TFloorWillBeLava.GetDataFileName: string;
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@ -33,6 +33,7 @@ type
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function CreateSolver: ISolver; override;
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published
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procedure TestPart1;
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procedure TestPart2;
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end;
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{ TFloorWillBeLavaExampleTestCase }
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@ -42,6 +43,7 @@ type
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function CreateSolver: ISolver; override;
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published
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procedure TestPart1;
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procedure TestPart2;
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end;
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implementation
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@ -58,6 +60,11 @@ begin
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AssertEquals(7392, FSolver.GetResultPart1);
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end;
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procedure TFloorWillBeLavaFullDataTestCase.TestPart2;
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begin
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AssertEquals(7665, FSolver.GetResultPart2);
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end;
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{ TFloorWillBeLavaExampleTestCase }
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function TFloorWillBeLavaExampleTestCase.CreateSolver: ISolver;
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@ -70,6 +77,11 @@ begin
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AssertEquals(46, FSolver.GetResultPart1);
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end;
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procedure TFloorWillBeLavaExampleTestCase.TestPart2;
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begin
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AssertEquals(51, FSolver.GetResultPart2);
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end;
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initialization
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RegisterTest(TFloorWillBeLavaFullDataTestCase);
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