This is a simple and pure sudoku puzzle solver with no other dependencies except the julia standard libraries. The package exports only one function, solvesudoku.
The solvesudoku function takes a 9×9 integer matrix or a string as input. In the integer matrix, blank is represented by the number 0. In the string, blank is represented by the character '0', '-', '.' or '_'. And invisible characters in the string, such as '\n', are ignored. Some sample puzzles can be found in SudokuSolver.PuzzleExamples. If the input is a valid puzzle, the function returns the solved sudoku puzzle as a 9×9 integer matrix; otherwise, it returns nothing. If the puzzle has more than one solution, only one of them will be returned.
using SudokuSolver@show SudokuSolver.PuzzleExamples[9]
solvesudoku(SudokuSolver.PuzzleExamples[9])
SudokuSolver.PuzzleExamples[9] = [
6 0 8 0 5 0 0 0 1;
5 0 4 9 3 0 0 0 6;
0 0 0 0 0 6 9 7 5;
7 4 9 8 2 0 0 0 3;
3 8 2 0 0 0 0 0 9;
0 0 5 0 9 0 0 0 0;
0 5 0 0 6 8 0 0 4;
8 3 0 0 0 0 0 5 7;
0 0 0 0 0 0 6 0 0]
9×9 Matrix{Int64}:
6 9 8 7 5 2 4 3 1
5 7 4 9 3 1 8 2 6
2 1 3 4 8 6 9 7 5
7 4 9 8 2 5 1 6 3
3 8 2 6 1 7 5 4 9
1 6 5 3 9 4 7 8 2
9 5 7 2 6 8 3 1 4
8 3 6 1 4 9 2 5 7
4 2 1 5 7 3 6 9 8@show SudokuSolver.PuzzleExamples[3]
solvesudoku(SudokuSolver.PuzzleExamples[3])
SudokuSolver.PuzzleExamples[3] = """
--53-----
8------2-
-7--1-5--
4----53--
-1--7---6
--32---8-
-6-5----9
--4----3-
-----97--"""
9×9 Matrix{Int64}:
1 4 5 3 2 7 6 9 8
8 3 9 6 5 4 1 2 7
6 7 2 9 1 8 5 4 3
4 9 6 1 8 5 3 7 2
2 1 8 4 7 3 9 5 6
7 5 3 2 9 6 4 8 1
3 6 7 5 4 2 8 1 9
9 8 4 7 6 1 2 3 5
5 2 1 8 3 9 7 6 4@show SudokuSolver.PuzzleExamples[4]
solvesudoku(SudokuSolver.PuzzleExamples[4])
SudokuSolver.PuzzleExamples[4] = "98.7..6..7......8...6.5....4....3..2..794..6.......4...1......3..95...7.....2.1.."
9×9 Matrix{Int64}:
9 8 5 7 3 2 6 4 1
7 3 2 1 6 4 9 8 5
1 4 6 8 5 9 2 3 7
4 9 1 6 8 3 7 5 2
2 5 7 9 4 1 3 6 8
8 6 3 2 7 5 4 1 9
6 1 8 4 9 7 5 2 3
3 2 9 5 1 6 8 7 4
5 7 4 3 2 8 1 9 6A mini benchmark compared with package Sudoku.jl v0.1.1.
using BenchmarkTools
using SudokuSolver
using Sudoku
# Sudoku.jl
@btime begin
sudoku(Sudoku.puzz1)
sudoku(Sudoku.puzz2)
sudoku(Sudoku.puzz3)
end
31.393 ms (93863 allocations: 8.48 MiB)
# our SudokuSolver.jl
@btime begin
solvesudoku(Sudoku.puzz1)
solvesudoku(Sudoku.puzz2)
solvesudoku(Sudoku.puzz3)
end
1.100 ms (6 allocations: 2.58 KiB)
# Sudoku.jl
@btime for puzzle in SudokuSolver.PuzzleExamples
p = SudokuSolver.loadpuzzle(puzzle)
sudoku(p)
end
2.923 s (313555 allocations: 28.31 MiB)
# our SudokuSolver.jl
@btime for puzzle in SudokuSolver.PuzzleExamples
p = SudokuSolver.loadpuzzle(puzzle)
solvesudoku(p)
end
64.592 ms (80 allocations: 25.78 KiB)