using System;

using System.Collections.Generic;

using System.Linq;

​

public class SchoolClass

{

    public List<string> Students { get; set; }

}

public class Program

{

    public static void Main()

    {

        List<string> searchedStudents = new() { "Brian", "Adrian", "Matt", "Chloe" };

        List<SchoolClass> schoolClasses = new()

        {

            new() { Students = new() { "Brian", "Zara" } },

            new() { Students = new() { "Sophie", "Zara" } },

        };

        // Using foreach loop

        var matchingSchoolClasses = new List<SchoolClass>();

​

        foreach (var schoolClass in schoolClasses)

        {

            if (schoolClass.Students.Intersect(searchedStudents).Any())

            {

                matchingSchoolClasses.Add(schoolClass);

            }

        }

        // Using .Where()

        var matchingSchoolClasses2 = schoolClasses

            .Where(schoolClass => schoolClass.Students.Intersect(searchedStudents).Any())

            .ToList();

        // Print results

        PrintStudents(matchingSchoolClasses);

        PrintStudents(matchingSchoolClasses2);

    }

    private static void PrintStudents(List<SchoolClass> schoolClasses)

    {

        foreach (var schoolClass in schoolClasses)

        {

            Console.WriteLine($"Students in matching school class: [ {string.Join(", ", schoolClass.Students)} ]");

        }

    }

}