public boolean isValidSudoku(char[][] board) {
		if ((board == null) || (board.length % 3 != 0) || (board.length != board[0].length))
			return false;
		for (int y = 0; y < board.length; y++) {
			for (int x = 0; x < board.length; x++) {
				if (board[y][x] == '.') {
					continue;
				}
				if (isValidInRow(x, y, board) && isValidInColumn(x, y, board) && isValidInRegion(x, y, board)) {
					continue;
				} else {
					return false;
				}
			}
		}
		return true;
	}