Initialized class + working Participant.cs class

Marathons/Marathon.cs

@@ -1,3 +1,35 @@
 namespace Marathons;
 
-// TODO
+public sealed class Marathon
+{
+    //private Node? _head;
+    public readonly string City;
+    public readonly DateOnly Date;
+    public int ParticipantCount { get; private set; }
+    
+    public Marathon(string city, DateOnly date)
+    {
+        City = city;
+        Date = date;
+    }
+
+    public void AddParticipant(Participant participant)
+    {
+        
+    }
+
+    public bool RemoveParticipant(int index)
+    {
+        return false;
+    }
+
+    public string[] GetResultList()
+    {
+        return Array.Empty<string>();
+    }
+
+    public override string ToString()
+    {
+        return $"{City} marathon on {Date.ToString()}";
+    }
+}

Marathons/Node.cs

@@ -0,0 +1,7 @@
+namespace Marathons;
+
+public sealed class Node(double? value)
+{
+    public double? Data { get; } = value;
+    public Node? Next { get; set; }
+}

Marathons/Participant.cs

@@ -1,3 +1,37 @@
 namespace Marathons;
 
-// TODO
+public sealed class Participant
+{
+    public readonly int StartNo;
+    public readonly string Name;
+    public readonly TimeSpan CompletionTime;
+    
+    public Participant(int startNo, string name, TimeSpan completionTime)
+    {
+        StartNo = startNo;
+        Name = name;
+        CompletionTime = completionTime;
+    }
+
+    public int CompareTo(Participant participant)
+    {
+        // Check if the completion time and startno is the same
+        if (CompletionTime == participant.CompletionTime && StartNo == participant.StartNo)
+        {
+            return 0;
+        }
+        
+        // Check if the completion time is the same
+        if(CompletionTime == participant.CompletionTime)
+        {
+            return StartNo < participant.StartNo ? -1 : 1;
+        }
+        
+        return CompletionTime < participant.CompletionTime ? -1 : 1;
+    }
+    
+    public override string ToString()
+    {
+        return $"{Name} (Start# {StartNo:000}) finished in {CompletionTime}";
+    }
+}