QuickSudoku

Sudoku puzzle solver, grader, and generator.

This project is an incomplete work-in-progress.

CLI Usage

QuickSudoku Solver 0.2.1-alpha
Copyright (c) 2022-2025 Fabio Iotti.

Usage:
  Solver --generate
  cat "(puzzle scheme)" | Solver --in
  Solver "(puzzle scheme)"

Puzzle scheme format:
  53. .7. ...
  6.. 195 ...
  .98 ... .6.

  8.. .6. ..3
  4.. 8.3 ..1
  7.. .2. ..6

  .6. ... 28.
  ... 419 ..5
  ... .8. .79

To generate a new random puzzle, grade it, and print the solution:

Solver --generate

To print the step-by-step solution for an existing puzzle:

# Bash (Unix shell)

Solver "
  53. .7. ...
  6.. 195 ...
  .98 ... .6.

  8.. .6. ..3
  4.. 8.3 ..1
  7.. .2. ..6

  .6. ... 28.
  ... 419 ..5
  ... .8. .79
"

:: Windows cmd.exe

(
  echo 53. .7. ...
  echo 6.. 195 ...
  echo .98 ... .6.

  echo 8.. .6. ..3
  echo 4.. 8.3 ..1
  echo 7.. .2. ..6

  echo .6. ... 28.
  echo ... 419 ..5
  echo ... .8. .79
) | Solver --in

Library Usage

To generate a new easy puzzle:

SudokuPuzzle puzzle = SudokuGenerator.Generate(new()
{
    Symmetry = SudokuSymmetry.Full,
    LimitStrategy = SudokuSolutionStrategy.HiddenPair,
});

for (int y = 0; y < 9; y++)
{
    for (int x = 0; x < 9; x++)
    {
        Console.Write("{0}", puzzle[x, y].Value?.ToString() ?? " ");
    }

    Console.WriteLine();
}

To solve and grade a puzzle:

SudokuPuzzle puzzle = SudokuPuzzle.FromScheme(@"
    53. .7. ...
    6.. 195 ...
    .98 ... .6.

    8.. .6. ..3
    4.. 8.3 ..1
    7.. .2. ..6

    .6. ... 28.
    ... 419 ..5
    ... .8. .79
");

ISudokuSolutionLog solution = SudokuSolver.Solve(puzzle);

Console.WriteLine("Difficulty: {0}", solution.Difficulty);

License

Copyright (c) 2022-2025 Fabio Iotti

This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, version 3 of the License.

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 Affero General Public License for more details.

You should have received a copy of the GNU Affero General Public License along with this program. If not, see https://www.gnu.org/licenses/.

Some files may be licensed under different terms, refer to the header at the beginning of each individual file for file-specific licenses.