Question

-----JAVA----

Implement a linear-time static method called mergeSortedthat merges two sorted Stringarrays, producing a new sorted Stringarray. Assume that the input arrays are in ascending (non-decreasing) alphabetic order. For example, if the first input array is [ "cats", "hogs" ] and the second input array is ["dogs", "frogs" ], then mergeSortedreturns the array [ “cats”, “dogs”, “frogs”, “hogs” ]. Note that the inputs may be null or empty. If any input array is null or empty, then the output array should contain the elements from the non-empty one.

Hint: Keep an index into each array to process each element. Repeatedly append the smallest unprocessed element from either array and advance the index accordingly.

Answer 1

Here is the completed code for this problem in Java. Comments are included, go through it, learn how things work and let me know if you have any doubts or if you need anything to change. If you are satisfied with the solution, please rate the answer. Thanks

// required method

public static String[] mergeSorted(String arr1[], String arr2[]) {

      // if arr1 is null, initializing arr1 with 0 as length

      if (arr1 == null) {

            arr1 = new String[0];

      }

      // if arr2 is null, initializing arr2 with 0 as length

      if (arr2 == null) {

            arr2 = new String[0];

      }

      // creating a result array with enough capacity

      String result[] = new String[arr1.length + arr2.length];

      // defining three index variables

      int index1 = 0, index2 = 0, index3 = 0;

      // looping as long as index1 is valid in arr1 and index2 is valid in

      // arr2

      while (index1 < arr1.length && index2 < arr2.length) {

            // checking if arr1[index1] is smaller than or equal to arr2[index2]

            if (arr1[index1].compareTo(arr2[index2]) <= 0) {

                  // adding arr1[index1] to result array and incrementing index1

                  result[index3] = arr1[index1];

                  index1++;

            } else {

                  // adding arr2[index2] to result array and incrementing index2

                  result[index3] = arr2[index2];

                  index2++;

            }

            // updating index3

            index3++;

      }

      // now if the lengths of arrays are different, there might be still

      // elements left in either arrays (but not both), if yes, adding all

      // those elements to result

      // adding remaining elements in arr1 (if exists) to result

      while (index1 < arr1.length) {

            result[index3] = arr1[index1];

            index1++;

            index3++;

      }

      // adding remaining elements in arr2 (if exists) to result

      while (index2 < arr2.length) {

            result[index3] = arr2[index2];

            index2++;

            index3++;

      }

      //returning the result array

      return result;

}