Implement intersection & union in LinkedList

Q. Write a Java program to implement following options on LinkedList using collections.

  • Intersection
  • Union
  • Display
Answer:

In this example, we create two list to perform intersection and union. In intersection only common elements are printed on both linkedlist. The union operation prints all the elements on the given list.

LinkedListTest.java

import java.util.*;
public class LinkedListTest
{
     public <T> List<T> union(List<T> list1, List<T> list2)
     {
          Set<T> set = new HashSet<T>();
          set.addAll(list1);
          set.addAll(list2);
          return new LinkedList<T>(set);
     }
     public <T> List<T> intersection(List<T> list1, List<T> list2)
     {
          List<T> list = new LinkedList<T>();
          for (T t : list1)
          {
               if(list2.contains(t))
               {
                    list.add(t);
               }
          }
          return list;
     }
     public static void main(String... args) throws Exception
     {
          List<String> list1 = new LinkedList<String>(Arrays.asList("A", "B", "C"));
          List<String> list2 = new LinkedList<String>(Arrays.asList("B", "C", "D", "E", "F"));
          //Display the record from LinkedList
          System.out.println("===========================");
          System.out.println("Intersection of LinkedList.");
          System.out.println(new LinkedListTest().intersection(list1, list2));
          System.out.println("=========================\n");
          System.out.println("Union of LinkedList.");
          System.out.println(new LinkedListTest().union(list1, list2));
          System.out.println("========================\n");
     }

}


Output:

intersection union
▲