Question

Write a method that takes two arrays of integers and return and array that is the union of both arrays. For instance, the first array contains (1,2,3), the second array(4,5,6), the returned array should contain (1,2,3,4,5,6) (3.5 points) Write a method that takes and an array and return the reverse of that array. For instance, if the array is (1,2,3), the returned array should be (3,2,1) (3.5 points)

Answer 1

import java.util.Arrays;

public class ArrayMethods {

    // union method
    public static int[] union(int[] arr1, int[] arr2) {
        int[] result = new int[arr1.length + arr2.length];
        int index = 0;
        for (int i = 0; i < arr1.length; i++) {
            result[index++] = arr1[i];
        }
        for (int i = 0; i < arr2.length; i++) {
            result[index++] = arr2[i];
        }
        return result;
    }

    // reverse method
    public static int[] reverse(int[] arr) {
        int[] result = new int[arr.length];
        for (int i = 0; i < arr.length; i++) {
            result[arr.length - i - 1] = arr[i];
        }
        return result;
    }

    // main method for testing. ignore it if not required
    public static void main(String[] args) {
        System.out.println(Arrays.toString(union(new int[]{1, 2, 3}, new int[]{4, 5, 6})));
        System.out.println(Arrays.toString(reverse(new int[]{1, 2, 3})));
    }
}

[1, 2, 3, 4, 5, 6] [3, 2, 1] Process finished with exit code 0