public static int[] twoDimensionalToOneDimensional(int[][] arr) if arr is null then return null 3. otherwise (i) copy the non-null rows of arr to a one-dimensional array and (ii) return the one-dimensional array. arr can contain null rows . the length of the returned array should be equal to the number of integers stored in the non-null rows of arr; hint: use the result from method 1 to find the length of this array. copy the non-null rows in ascending order. In other words, first copy row 0 to the one-dimensional array, then row 1, 2, etc. if all the rows contained in arr are null then return an array whose length is zero. use the System.arraycopy method to copy the non-null rows of arr to the one-dimensional array . Example: Assume arr 11, 20, 50), {5, 8), null, 122, 100, 200, 1); The method returns the following one-dimensional array: 11, 20, 50, 5, 8, 22, 100, 200, 1) 4. public static int[] threeDimensionalToOneDimensional(int[]]] arr) if arr is null then return null otherwise (i) copy the non-null two-dimensional arrays in arr to a one- dimensional array and (ii) return the one-dimensional array. . arr may contain two-dimensional arrays that are set to null. the length of the returned array should be equal to the number of integers stored in the non-null two-dimensional arrays. copy the non-null two-dimensional arrays in ascending order. In other words, first copy array 0 to the one-dimensional array, then array 1, 2, etc. if all two-dimensional arrays contained in arr are null then return an array whose length is zero. for every non-null array stored in arr, use the System.arraycopy method to copy the result from twoDimensionalToOneDimensional into the one- dimensional array . . Example: Assume arr-{ {null, {9, 0, 8}, null, {0, 7, 6, 3, 4)}, {19, 1, 50), {99, 11), (6^, null f8, 9, 45, 8, 0), {6, 7, 2},