SudokuSolver.j

gistfile1.txt

var board = [
  [4, 5, '.', 8, '.', '.', 9, '.', '.'],
  ['.', 9, '.', '.', 5, 6, '.', '.', 4],
  [1, '.', '.', '.', '.', '.', '.', '.', 7],
  [2, 6, '.', 5, 4, '.', '.', 9, '.'],
  ['.', '.', 4, 1, '.', 2, 3, '.', '.'],
  ['.', 7, '.', '.', 6, 9, '.', 4, 8],
  [7, '.', '.', '.', '.', '.', '.', '.', 9],
  [8, '.', '.', 4, 9, '.', '.', 7, '.'],
  ['.', '.', 9, '.', '.', 3, '.', 2, 5],
]

//sudokuMagician

//Note: run 17-19 outside of sudokuMagician
// 3 arrays with nested arrays for used numbers in subgrids rows, and columns

var subgrids = {
  /*
  0: {
    changed: false,
    usedNumbers: [1, 2, 3],
  },
  1: ...
  */
}

// loop through each subgrid to find used numbers
const subgridUsedNumbers = (rowStartIndex, columnStartIndex, gameBoard) => {
  let usedNumbers = [];
  for (let i = rowStartIndex; i < rowStartIndex + 3; i++) {
    for (let x = columnStartIndex; x < columnStartIndex + 3; x++) {
      if (gameBoard[i][x] !== '.') {
        usedNumbers.push(gameBoard[i][x]);
      };
    };
  };
  return usedNumbers;  
};

// loop through rows to find used numbers
const rowUsedNumbers = (rowIndex, gameBoard) => {
  let usedNumbers = [];
  for (let x = 0; x < 9; x++) {
    if (gameBoard[rowIndex][x] !== '.') {
      usedNumbers.push(gameBoard[rowIndex][x]);
    };
  };
  return usedNumbers;
};

// loop through columns to find used numbers
const columnUsedNumbers = (columnIndex, gameBoard) => {
  let usedNumbers = [];
  for (let x = 0; x < 9; x++) {
    if (gameBoard[x][columnIndex] !== '.') {
      usedNumbers.push(gameBoard[x][columnIndex]);
    };
  };
  return usedNumbers;
};

// return all unused numbers
const allUnUsedNumbers = (rowIndex, columnIndex, gameBoard) => {
  let usedNumbers = [];

  let usedSubgridNumbers = subgridUsedNumbers(rowIndex, columnIndex, gameBoard);
  let usedRowNumbers = rowUsedNumbers(rowIndex, gameBoard);
  let usedColumnNumbers = columnUsedNumbers(columnIndex, gameBoard);

  for (let i = 0; i < 9; i++) {
    usedSubgridNumbers
  };
}

// let stillGoing = true;

const sudokuMagician = (gameBoard) => {
//conitnually loop until there are no more found '.' for a full loop
  // while (stillGoing) {
    let dotsLeft = []
    //loop i for 9 itterations
    for (let i = 0; i < 9; i++) {
      //loop x for 9 itterations
      for (let x = 0; x < 9; x++) {
        //if gameBoard square at row i and column x is '.'
        if (gameBoard[i][x] === '.') {
          dotsLeft.push('.');
          //declare possibleOutcomes as an array
          let possibleOutcomes = [];
          let usedGridNumbers = subgridUsedNumbers(Math.floor(i/3), Math.floor(x/3), gameBoard);
          let usedRowNumbers = rowUsedNumbers(i, gameBoard);
          let usedColumnNumbers = columnUsedNumbers(x, gameBoard);
          
          // loop through 9-1 y
          for (let y = 9; y > 0; y--) {        
            // if y is not in the specific subgrid, row, or column
            // Todo: could do only once out of loop then search one array
            let gridNumberUsed = usedGridNumbers.indexOf(y);
            let usedRowNumber = usedRowNumbers.indexOf(y);
            let usedColumnNumber = usedColumnNumbers.indexOf(y);

            if (gridNumberUsed < 0 && usedRowNumber < 0 && usedColumnNumber < 0) {
              // add y to possibleOutcomes via push
              possibleOutcomes.push(y);
            };
            
          };
          
          // if possibleOutcomes length is 1
          if (possibleOutcomes.length === 1) {
            // replace '.' with y on the board at row i and column x
            gameBoard[i][x] = possibleOutcomes[0];
          };
        };
      };
    };
    if (dotsLeft.length = 0) {
      stillGoing = true;
    }
  // };
}
          
          
sudokuMagician(board);

console.log('board==', board);