Question

Question 1: Write the following method that returns a new ArrayList. The new list contains the nonduplicate elements from the original list,

public static <E> ArrayList<E> removeDuplicates(ArrayList<E> list)

Question 2:

Implement the following method that returns the maximum element in an array:

public static <E extends Comparable<E>> E max(E[] list)

Each question is its own code and it must be able to run. Please show details .

Thank you in advance!

Answer 1

import java.util.ArrayList;
import java.util.Arrays;

public class RemoveDuplicates {

    public static <E> ArrayList<E> removeDuplicates(ArrayList<E> list) {
        ArrayList<E> newList = new ArrayList<>();
        for(int i = 0; i < list.size(); ++i) {
            if(!newList.contains(list.get(i))) {
                newList.add(list.get(i));
            }
        }
        return newList;
    }

    public static void main(String[] args) {
        ArrayList<Integer> numbers = new ArrayList<>(Arrays.asList(1, 8, 2, 8, 1, 4, 2, 6));
        System.out.println("Original list = " + numbers);
        System.out.println("List after removing duplicates = " + removeDuplicates(numbers));
    }
}

public class GenericMaxComparable {

    public static <E extends Comparable<E>> E max (E [] list) {
        E maxValue = list[0];
        for(int i = 0; i < list.length; i++) {
            if(list[i].compareTo(maxValue) > 0) {
                maxValue = list[i];
            }
        }
        return maxValue;
    }

    public static void main(String[] args) {
        String[] colors = {"Red","Green","Blue"};
        Integer[] numbers = {1, 2, 3};
        Double[] doubles = {3.0, 5.9, 2.9};

        System.out.println("Colors: " + max(colors));
        System.out.println("Numbers: " + max(numbers));
        System.out.println("Circle11 Radius: " + max(doubles));
    }

}