Math - Symmetric Difference

Part of the Logic & Flow section of Coddy's Java journey — lesson 32 of 59.

The symmetric difference of two sets is a new set that contains elements that are in either set but not in both. In Java, you can compute it by:

Finding the difference of the first set with respect to the second.

Finding the difference of the second set with respect to the first.

Combining these two differences.

First, create two HashSets:

HashSet<Integer> set1 = new HashSet<>();
set1.add(1);
set1.add(2);
set1.add(3);

HashSet<Integer> set2 = new HashSet<>();
set2.add(2);
set2.add(3);
set2.add(4);

Next, compute each one-way difference:

HashSet<Integer> diff1 = new HashSet<>(set1);
diff1.removeAll(set2);  // diff1 is [1]
HashSet<Integer> diff2 = new HashSet<>(set2);
diff2.removeAll(set1);  // diff2 is [4]

Next, combine the two differences:

diff1.addAll(diff2);  // diff1 is [1, 4]

Challenge

Easy

Create a method named <strong>symmetricDifference</strong> that takes two HashSets of integers as input, computes their symmetric difference, and prints it in the format:

Symmetric Difference: [elements]

Try it yourself

import java.util.HashSet;
import java.util.Scanner;
import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;
import java.lang.reflect.Type;

public class Main {
    public static void symmetricDifference(HashSet<Integer> set1, HashSet<Integer> set2) {
        // Write your code here
    }

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        // Read JSON string for the first set (e.g., [1,2,3])
        String set1String = scanner.nextLine();
        // Read JSON string for the second set (e.g., [2,3,4])
        String set2String = scanner.nextLine();

        Type setType = new TypeToken<HashSet<Integer>>(){}.getType();
        HashSet<Integer> set1 = new Gson().fromJson(set1String, setType);
        HashSet<Integer> set2 = new Gson().fromJson(set2String, setType);

        symmetricDifference(set1, set2);
    }
}