40. Gra Sudoku

// Walidacja reguł Sudoku
function isValidPlacement(board, row, col, num) {
  // Sprawdzenie wiersza
  for (let c = 0; c < 9; c++) {
    if (board[row][c] === num && c !== col) return false;
  }
  // Sprawdzenie kolumny
  for (let r = 0; r < 9; r++) {
    if (board[r][col] === num && r !== row) return false;
  }
  // Sprawdzenie kwadratu 3×3
  const boxRow = Math.floor(row / 3) * 3;
  const boxCol = Math.floor(col / 3) * 3;
  for (let r = boxRow; r < boxRow + 3; r++) {
    for (let c = boxCol; c < boxCol + 3; c++) {
      if (board[r][c] === num && (r !== row || c !== col)) return false;
    }
  }
  return true;
}

function useSudoku(initialBoard) {
  const [board, setBoard] = useState(initialBoard.map((row) => [...row]));
  const [selected, setSelected] = useState(null);
  const [errors, setErrors] = useState(new Set());

  function setCell(row, col, num) {
    if (initialBoard[row][col] !== 0) return; // komórka wstępnie wypełniona
    const newBoard = board.map((r) => [...r]);
    newBoard[row][col] = num;

    // Znajdź konflikty
    const newErrors = new Set();
    for (let r = 0; r < 9; r++) {
      for (let c = 0; c < 9; c++) {
        if (newBoard[r][c] !== 0 && !isValidPlacement(newBoard, r, c, newBoard[r][c])) {
          newErrors.add(`${r}-${c}`);
        }
      }
    }
    setErrors(newErrors);
    setBoard(newBoard);
  }

  const isComplete = board.every((row) => row.every((cell) => cell !== 0)) && errors.size === 0;
  return { board, selected, setSelected, setCell, errors, isComplete };
}