public class Sudoku {
	private int[][] board;

	// Constructor - Throws IllegalArgumentException if input matrix is not
	// Sudoku-formatted
	public Sudoku(int[][] board) {
		if (board.length == 9 && board[0].length == 9) {
			this.board = board;
		} else {
			throw new IllegalArgumentException("Input matrix is not Sudoku-formatted");
		}
	}

	// Returns value at row i column j, Throws IllegalArgumentException if index
	// is out of bounds
	public int getValue(int i, int j) {
		if (i < 9 && j < 9 && i >= 0 && j >= 0) {
			return board[i][j];
		} else {
			throw new IllegalArgumentException("Index out of bounds");
		}
	}

	// Sets value in matrix, Throws IllegalArgumentException if index
	// is out of bounds
	public void setValue(int i, int j, int value) {
		if (i < 9 && j < 9 && i >= 0 && j >= 0) {
			board[i][j] = value;
		} else {
			throw new IllegalArgumentException("Index out of bounds");
		}
	}
}