Data commit

Task/Sudoku/Delphi/sudoku-1.delphi

@@ -0,0 +1,125 @@
+type
+  TIntArray = array of Integer;
+
+  { TSudokuSolver }
+
+  TSudokuSolver = class
+  private
+    FGrid: TIntArray;
+
+    function CheckValidity(val: Integer; x: Integer; y: Integer): Boolean;
+    function ToString: string; reintroduce;
+    function PlaceNumber(pos: Integer): Boolean;
+  public
+    constructor Create(s: string);
+
+    procedure Solve;
+  end;
+
+implementation
+
+uses
+  Dialogs;
+
+{ TSudokuSolver }
+
+function TSudokuSolver.CheckValidity(val: Integer; x: Integer; y: Integer
+  ): Boolean;
+var
+  i: Integer;
+  j: Integer;
+  StartX: Integer;
+  StartY: Integer;
+begin
+  for i := 0 to 8 do
+  begin
+    if (FGrid[y * 9 + i] = val) or
+       (FGrid[i * 9 + x] = val) then
+    begin
+      Result := False;
+      Exit;
+    end;
+  end;
+  StartX := (x div 3) * 3;
+  StartY := (y div 3) * 3;
+  for i := StartY to Pred(StartY + 3) do
+  begin
+    for j := StartX to Pred(StartX + 3) do
+    begin
+      if FGrid[i * 9 + j] = val then
+      begin
+        Result := False;
+        Exit;
+      end;
+    end;
+  end;
+  Result := True;
+end;
+
+function TSudokuSolver.ToString: string;
+var
+  sb: string;
+  i: Integer;
+  j: Integer;
+  c: char;
+begin
+  sb := '';
+  for i := 0 to 8 do
+  begin
+    for j := 0 to 8 do
+    begin
+      c := (IntToStr(FGrid[i * 9 + j]) + '0')[1];
+      sb := sb + c + ' ';
+      if (j = 2) or (j = 5) then sb := sb + '| ';
+    end;
+    sb := sb + #13#10;
+    if (i = 2) or (i = 5) then
+      sb := sb + '-----+-----+-----' + #13#10;
+  end;
+  Result := sb;
+end;
+
+function TSudokuSolver.PlaceNumber(pos: Integer): Boolean;
+var
+  n: Integer;
+begin
+  Result := False;
+  if Pos = 81 then
+  begin
+    Result := True;
+    Exit;
+  end;
+  if FGrid[pos] > 0 then
+  begin
+    Result := PlaceNumber(Succ(pos));
+    Exit;
+  end;
+  for n := 1 to 9 do
+  begin
+    if CheckValidity(n, pos mod 9, pos div 9) then
+    begin
+      FGrid[pos] := n;
+      Result := PlaceNumber(Succ(pos));
+      if not Result then
+        FGrid[pos] := 0;
+    end;
+  end;
+end;
+
+constructor TSudokuSolver.Create(s: string);
+var
+  lcv: Cardinal;
+begin
+  SetLength(FGrid, 81);
+  for lcv := 0 to Pred(Length(s)) do
+    FGrid[lcv] := StrToInt(s[Succ(lcv)]);
+end;
+
+procedure TSudokuSolver.Solve;
+begin
+  if not PlaceNumber(0) then
+    ShowMessage('Unsolvable')
+  else
+    ShowMessage('Solved!');
+  end;
+end;

Task/Sudoku/Delphi/sudoku-2.delphi

@@ -0,0 +1,18 @@
+var
+  SudokuSolver: TSudokuSolver;
+begin
+  SudokuSolver := TSudokuSolver.Create('850002400' +
+                                       '720000009' +
+                                       '004000000' +
+                                       '000107002' +
+                                       '305000900' +
+                                       '040000000' +
+                                       '000080070' +
+                                       '017000000' +
+                                       '000036040');
+  try
+    SudokuSolver.Solve;
+  finally
+    FreeAndNil(SudokuSolver);
+  end;
+end;