Sudoku Checker Solution

sudoku-checker.js

export const checkSudoku = (board) => {
  for (let i = 0; i < 4; i++) {
    const row = new Set();
    const col = new Set();
    const square = new Set();
    for (let j = 0; j < 4; j++) {
      const rowEl = board[i][j];
      const colEl = board[j][i];
      const squareEl =
        board[2 * Math.floor(i / 2) + Math.floor(j / 2)][2 * (i % 2) + (j % 2)];

      if (row.has(rowEl) || col.has(colEl) || square.has(squareEl)) {
        return false;
      }
      row.add(rowEl);
      col.add(colEl);
      square.add(squareEl);
    }
  }

  return true;
};

export const checkSudokuFull = (board) => {
  for (let i = 0; i < 9; i++) {
    const row = new Set();
    const col = new Set();
    const square = new Set();
    for (let j = 0; j < 9; j++) {
      const rowEl = board[i][j];
      const colEl = board[j][i];
      const squareEl =
        board[3 * Math.floor(i / 3) + Math.floor(j / 3)][3 * (i % 3) + (j % 3)];

      if (row.has(rowEl) || col.has(colEl) || square.has(squareEl)) {
        return false;
      }
      row.add(rowEl);
      col.add(colEl);
      square.add(squareEl);
    }
  }

  return true;
};