Math - Symmetric Difference

Part of the Logic & Flow section of Coddy's C# journey — lesson 65 of 66.

The symmetric difference of two sets contains elements that are in either of the sets, but not in their intersection (elements that appear in exactly one of the sets).

Create two HashSet objects:

HashSet<int> set1 = new HashSet<int>() { 1, 2, 3, 4 };
HashSet<int> set2 = new HashSet<int>() { 3, 4, 5, 6 };

Create a new HashSet for the result:

HashSet<int> symmetricDifference = new HashSet<int>(set1);

Use the SymmetricExceptWith method to compute the symmetric difference:

symmetricDifference.SymmetricExceptWith(set2);

After executing the above code, the symmetricDifference set contains:

{ 1, 2, 5, 6 }

The elements 3 and 4 are in both sets, so they don't appear in the symmetric difference.

Challenge

Easy

Create a method named FindSymmetricDifference that takes two arguments:

A HashSet of integers (set1)
A HashSet of integers (set2)

The method should return a new HashSet<int> containing the symmetric difference of the two sets. The rest of the program (reading input, sorting, and printing results) is already provided for you.

Cheat sheet

The symmetric difference of two sets contains elements that are in either set, but not in both (elements that appear in exactly one of the sets).

To find the symmetric difference, create a new HashSet from one set and use SymmetricExceptWith():

HashSet<int> set1 = new HashSet<int>() { 1, 2, 3, 4 };
HashSet<int> set2 = new HashSet<int>() { 3, 4, 5, 6 };

HashSet<int> symmetricDifference = new HashSet<int>(set1);
symmetricDifference.SymmetricExceptWith(set2);

Result: { 1, 2, 5, 6 } (elements 3 and 4 are excluded because they appear in both sets)

Try it yourself

using System;
using System.Collections.Generic;
using System.Linq;

class Program
{
    public static HashSet<int> FindSymmetricDifference(HashSet<int> set1, HashSet<int> set2)
    {
        // Write your code here
    }
    
    static void Main(string[] args)
    {
        string[] input1 = Console.ReadLine().Split(',');
        string[] input2 = Console.ReadLine().Split(',');
        
        HashSet<int> set1 = new HashSet<int>();
        HashSet<int> set2 = new HashSet<int>();
        
        foreach (string s in input1)
        {
            if (int.TryParse(s.Trim(), out int num))
            {
                set1.Add(num);
            }
        }
        
        foreach (string s in input2)
        {
            if (int.TryParse(s.Trim(), out int num))
            {
                set2.Add(num);
            }
        }
        
        HashSet<int> result = FindSymmetricDifference(set1, set2);
        
        // Print the result in ascending order
        int[] orderedResult = result.OrderBy(x => x).ToArray();
        foreach (int num in orderedResult)
        {
            Console.WriteLine(num);
        }
    }
}