Basic universe management, generation and simulation flow

scripts/FastUniqueList.cs

@@ -0,0 +1,49 @@
+using System;
+using System.Collections.Generic;
+
+public class FastUniqueList<T>
+{
+    private readonly List<T> list = [];
+    private readonly HashSet<T> set = [];
+
+    public int Count => list.Count;
+
+    public T this[int index] => list[index];
+
+    public bool Contains(T item)
+    {
+        return set.Contains(item);
+    }
+
+    public bool Add(T item)
+    {
+        if (!set.Add(item))
+        {
+            return false;
+        }
+
+        list.Add(item);
+        return true;
+    }
+
+    public bool Remove(T item)
+    {
+        if (!set.Remove(item))
+        {
+            return false;
+        }
+
+        int index = list.IndexOf(item);
+        int last = list.Count - 1;
+
+        list[index] = list[last];
+        list.RemoveAt(last);
+
+        return true;
+    }
+
+    public void ForEach(Action<T> action)
+    {
+        list.ForEach(action);
+    }
+}