Sudoku Solver Asynchronous

a proper sudoku solver where the input has to be 9x9 and with a minimum of 17 clues, uses a brute force recursive backtracking algorithm. the function api has a 2nd optional parameter that allows you to 'hook' into each step in the callstack as the algorithm is executing in 'realtime', this is great for writing visualisations or other apps.

usage

basic usage

// sudoku puzzle input as a 2d array (can also be a 1d array)
const puzzleInput2dArr: number[][] = [
  [9, 1, 5, -1, -1, 3, 4, -1, 6],
  [-1, -1, -1, 1, -1, 2, -1, 8, 9],
  [-1, 6, -1, -1, -1, 4, 7, -1, 3],

  [-1, -1, -1, 3, 1, -1, -1, 9, -1],
  [5, -1, 8, -1, 4, -1, -1, 3, 2],
  [3, 4, 1, 8, -1, -1, -1, 5, -1],

  [-1, -1, -1, 4, 9, 6, -1, -1, -1],
  [2, 7, -1, -1, -1, -1, 9, -1, -1],
  [4, -1, 9, -1, -1, 1, 3, -1, 5],
];

(async () => {
  // function api usage
  const solvedSudoku: number[][] = await solveProperSudokuAsync(puzzleInput2dArr);
})();

example usage to write a visualisation (in the console) of a suduko puzzle being solved in realtime

// sudoku puzzle input as a 2d array (can also be as a 1d array)
const puzzleInput2dArr: number[][] = [
  [9, 1, 5, -1, -1, 3, 4, -1, 6],
  [-1, -1, -1, 1, -1, 2, -1, 8, 9],
  [-1, 6, -1, -1, -1, 4, 7, -1, 3],

  [-1, -1, -1, 3, 1, -1, -1, 9, -1],
  [5, -1, 8, -1, 4, -1, -1, 3, 2],
  [3, 4, 1, 8, -1, -1, -1, 5, -1],

  [-1, -1, -1, 4, 9, 6, -1, -1, -1],
  [2, 7, -1, -1, -1, -1, 9, -1, -1],
  [4, -1, 9, -1, -1, 1, 3, -1, 5],
];

(async () => {
  console.log("sudoku puzzle input");

  const formattedPuzzleInputAsString = puzzleInput2dArr
    .map((row) => row.map((cell) => (cell === -1 ? " " : cell)).join(" "))
    .join("\n");
  console.log(formattedPuzzleInputAsString);

  console.log("\n");

  // function api usage
  const solvedSudoku = await solveProperSudokuAsync(puzzleInput2dArr, {
    // 'hook' into each function call in the recursive call stack
    onFunctionExecutingInCallStack: (x, y, arr2d) => {

      // visualisation code start
      console.clear();
      console.log(`call stack n: ${y * 9 + x}, x: ${x}, y: ${y}`);
      const formattedResultAsString = arr2d
        .map((row) => row.map((cell) => (cell === -1 ? " " : cell)).join(" "))
        .join("\n");
      console.log(formattedResultAsString);
      // visualisation code end

    },

    // update/draw 10 times per second (will wait 1/10 of a second until calling next function in recursive algorithm)
    delayBetweenEachStepInCallStackInMillisecs: 1000 / 10,
  });

  // print result
  console.log("solved sudoku puzzle");
  const formattedResultAsString = solvedSudoku
    ?.map((row) => row.join(" "))
    .join("\n");
  console.log(formattedResultAsString);
})();

API Documentation

Function: solveProperSudokuAsync()

solveProperSudokuAsync(puzzleInput, callStackStep?): Promise<number[][]>

Solves a proper sudoku puzzle (9x9 with a minimum of 17 clues) with a recursive backtracking algorithm

Parameters

puzzleInput

a 9x9 2d array of numbers where -1 represents an empty cell

number[] | number[][]

callStackStep?

CallStackStep

Returns

Promise<number[][]>

a 9x9 2d array of numbers representing the solved sudoku puzzle

projects that use this package

sudoku solver async realtime visualisation web app

• sudoku solver async realtime visualisation web app (live link)
• github repository https://github.com/zoolu-got-rhythm/sudoku-solver-async-visualisation

If you end up writing any apps/visualisations that use this package, or find the package useful in any way would <3 to see or hear about it @ [email protected] and am happy to link it here. Happy Coding :)