In the provided file SudokuChecker.java, complete the following methods:

 public static boolean checkRow(int row, byte[][] grid) public static boolean checkColumn(int column, byte[][] grid) public static boolean checkSubregion(int region, byte[][] grid) 

These methods are used in the provided check method that takes a 2-dimensional (99) array of numbers and determines if it represents a valid (solved) sudoku grid of numbers. A valid sudoku grid has the following properties:

each row contains all of the digits from 1 to 9, each column contains all of the digits from 1 to 9, each of the nine 2-dimensional 33 subgregions contain all of the digits 1 to 9.

For example, the following is a valid sudoku grid (with n = 3). The nine subregions are shown shaded.

5	3	4	6	7	8	9	1	2
6	7	2	1	9	5	3	4	8
1	9	8	3	4	2	5	6	7
8	5	9	7	6	1	4	2	3
4	2	6	8	5	3	7	9	1
7	1	3	9	2	4	8	5	6
9	6	1	5	3	7	2	8	4
2	8	7	4	1	9	6	3	5
3	4	5	2	8	6	1	7	9

The rows are labelled 0 to 8 (from top to bottom), the columns are labelled 0 to 8 (from left to right), and the subregions are labelled 0 to 8 as follows:

0	1	2
3	4	5
6	7	8

SUDOKU CHECKER

public class SudokuChecker{ /** sample valid game */ public static byte[][] example1 = new byte[][]{ {5,3,4,6,7,8,9,1,2}, {6,7,2,1,9,5,3,4,8}, {1,9,8,3,4,2,5,6,7}, {8,5,9,7,6,1,4,2,3}, {4,2,6,8,5,3,7,9,1}, {7,1,3,9,2,4,8,5,6}, {9,6,1,5,3,7,2,8,4}, {2,8,7,4,1,9,6,3,5}, {3,4,5,2,8,6,1,7,9}}; /** sample invalid game */ public static byte[][] example2 = new byte[][]{ {5,3,4,6,7,8,9,1,2}, {6,7,2,1,9,5,3,4,8}, {1,9,8,3,4,2,5,6,7}, {8,5,9,7,6,1,4,2,3}, {4,2,6,8,5,3,7,9,1}, {7,1,3,9,2,4,8,5,6}, {9,6,1,5,3,7,2,8,3}, {2,8,7,4,1,9,6,2,6}, {3,4,5,2,8,6,1,8,8}}; /** checks if row 'row' is OK in the grid */ public static boolean checkRow(int row, byte[][] grid){ return true; } /** checks if column 'col' is OK in the grid */ public static boolean checkColumn(int col, byte[][] grid){ return true; } /** checks if the subregion 'region' is OK in the grid */ public static boolean checkSubregion(int region, byte[][] grid){ return true; } public static boolean check(byte[][] grid){ for(int row=0; row<9; row+=1){ // check the rows if( !checkRow(row, grid) ){ return false; } } for(int col=0; col<9; col+=1){ // check the rows if( !checkColumn(col, grid) ){ return false; } } for(int subregion=0; subregion<9; subregion+=1){ // check the subregions if( !checkSubregion(subregion, grid) ){ return false; } } // if we get this far then we conclude that the grid // must be valid (because if it was not, we would have // returned false somewhere above) return true; } public static void main(String[] args){ System.out.print("exmample1 | expected output is true | actual output is "); System.out.println(check(example1)); System.out.print("exmample2 | expected output is false | actual output is "); System.out.println(check(example2)); } }