The intersection of two sets is the set containing only the elements common to both sets

The intersection of two sets is the set containing only the elements common to both sets Write a java method that takes as parameters 2 sets and returns a LinkedHashSet containing the intersection of the two sets without changing the contents of the parameters

The Correct Answer and Explanation is:

Here’s a Java method that takes two sets as parameters and returns a LinkedHashSet containing their intersection:

javaCopyEditimport java.util.Set;
import java.util.LinkedHashSet;

public class SetIntersection {
    public static <T> LinkedHashSet<T> intersection(Set<T> set1, Set<T> set2) {
        // Create a LinkedHashSet to store the intersection of both sets
        LinkedHashSet<T> result = new LinkedHashSet<>();
        
        // Iterate over the first set
        for (T element : set1) {
            // If the element is also in the second set, add it to the result
            if (set2.contains(element)) {
                result.add(element);
            }
        }
        
        // Return the result, which contains only the common elements
        return result;
    }

    public static void main(String[] args) {
        Set<Integer> set1 = Set.of(1, 2, 3, 4, 5);
        Set<Integer> set2 = Set.of(4, 5, 6, 7, 8);

        // Calling the intersection method
        LinkedHashSet<Integer> result = intersection(set1, set2);

        // Printing the result
        System.out.println("Intersection: " + result); // Output: [4, 5]
    }
}

Explanation:

1. Method Declaration:
   The method intersection takes two sets of type T (generic type) as parameters. It returns a LinkedHashSet<T>, which preserves the order of elements from the first set while containing only those that are common to both sets.
2. LinkedHashSet:
   A LinkedHashSet is used to store the result because it maintains the insertion order while ensuring uniqueness (i.e., no duplicates).
3. For-Each Loop:
   The method iterates over the elements in set1. For each element, it checks if that element exists in set2 using the contains() method.
4. Adding to Result:
   If an element is found in both sets, it is added to the result set (LinkedHashSet).
5. Return the Result:
   The method returns the intersection set, containing only the common elements between set1 and set2.
6. Main Method:
   The main method demonstrates the functionality by creating two sets, calling the intersection() method, and printing the result.

Why This Works:

• The contains() method checks if each element of set1 is in set2, ensuring only common elements are added.
• LinkedHashSet is ideal here because it preserves insertion order, which is useful when you want to maintain the sequence of elements from the original sets.
• This method works with any type of Set (not just LinkedHashSet) because it uses the generic type T. This allows it to be reusable for any set type (like HashSet, TreeSet, etc.).

Efficiency:

• Time Complexity: The method runs in O(n * m) time, where n is the size of set1 and m is the size of set2, since the contains() method of a set generally runs in O(1) average time.