129 lines
3.1 KiB
Plaintext
129 lines
3.1 KiB
Plaintext
{
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Solutions to the Advent Of Code.
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Copyright (C) 2023 Stefan Müller
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This program is free software: you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free Software
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Foundation, either version 3 of the License, or (at your option) any later
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version.
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This program is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along with
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this program. If not, see <http://www.gnu.org/licenses/>.
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}
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unit UTrebuchet;
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{$mode ObjFPC}{$H+}
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interface
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uses
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Classes, SysUtils;
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type
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{ TTrebuchet }
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TTrebuchet = class(TObject)
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private
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FValue: Integer;
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procedure RunSolution;
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procedure ProcessDataLine(const ALine: string);
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function FindFirstDigit(const ALine: string; out OEndIndex: Integer): Integer;
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function FindLastDigit(const ALine: string; const AFirstDigit, AFirstDigitEndIndex: Integer): Integer;
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function CheckDigit(const ALine: string; const AIndex: Integer; out ODigit, OEndIndex: Integer): Boolean;
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public
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constructor Create;
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class procedure Solve; static;
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end;
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implementation
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{ TTrebuchet }
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procedure TTrebuchet.RunSolution;
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var
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data: TextFile;
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s: string;
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begin
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AssignFile(data, ConcatPaths(['data', 'trebuchet_calibration_document.txt']));
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try
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reset(data);
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while (not EOF(data)) do
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begin
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readln(data, s);
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ProcessDataLine(s);
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end;
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finally
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CloseFile(data)
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end;
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WriteLn('Part 1: ', FValue);
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end;
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procedure TTrebuchet.ProcessDataLine(const ALine: string);
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var
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first, endIndex, last: Integer;
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begin
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first := FindFirstDigit(ALine, endIndex);
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last := FindLastDigit(ALine, first, endIndex);
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Inc(FValue, first * 10 + last);
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end;
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function TTrebuchet.FindFirstDigit(const ALine: string; out OEndIndex: Integer): Integer;
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var
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i: Integer;
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begin
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for i := 1 to ALine.Length do
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if CheckDigit(ALine, i, Result, OEndIndex) then
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Exit;
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end;
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function TTrebuchet.FindLastDigit(const ALine: string; const AFirstDigit, AFirstDigitEndIndex: Integer): Integer;
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var
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i, endIndex: Integer;
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begin
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for i := ALine.Length downto AFirstDigitEndIndex + 1 do
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if CheckDigit(ALine, i, Result, endIndex) then
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Exit;
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// Returns the first digit if no digit was found after the end index of the first digit.
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Result := AFirstDigit;
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end;
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function TTrebuchet.CheckDigit(const ALine: string; const AIndex: Integer; out ODigit, OEndIndex: Integer): Boolean;
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begin
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if ALine[AIndex] in ['0'..'9'] then
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begin
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ODigit := StrToInt(ALine[AIndex]);
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OEndIndex := AIndex;
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Result := true;
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end
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else begin
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ODigit := -1;
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OEndIndex := -1;
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Result := false;
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end;
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end;
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constructor TTrebuchet.Create;
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begin
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FValue := 0;
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end;
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class procedure TTrebuchet.Solve;
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var
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trebuchet: TTrebuchet;
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begin
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WriteLn('--- Day 1: Trebuchet?! ---');
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trebuchet := TTrebuchet.Create;
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trebuchet.RunSolution;
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trebuchet.Free;
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end;
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end.
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