Первая стадия: массив заменён на список

SelfPropelledArtilleryUnit/SetArtilleriesGeneric.cs

@@ -9,12 +9,14 @@ namespace Artilleries
     internal class SetArtilleriesGeneric<T>
         where T : class
     {
-        private readonly T[] _places;
-        public int Count => _places.Length;
+        private readonly List<T> _places;
+        public int Count => _places.Count;
+        private readonly int _maxCount;
 
         public SetArtilleriesGeneric(int count)
         {
-            _places = new T[count];
+            _maxCount = count;
+            _places = new List<T>();
         }
 
         public int Insert(T artillery)
@@ -24,39 +26,13 @@ namespace Artilleries
 
         public int Insert(T artillery, int position)
         {
-            if (position < 0 || position >= Count)
+            if (position < 0 || position >= Count || Count == _maxCount)
             {
                 return -1;
             }
 
-            if (_places[position] == null)
-            {
-                _places[position] = artillery;
-                return position;
-            }
+            _places.Insert(position, artillery);
 
-            int firstNull = -1;
-
-            for (int i = position + 1; i < Count; i++)
-            {
-                if (_places[i] == null)
-                {
-                    firstNull = i;
-                    break;
-                }
-            }
-
-            if (firstNull == -1)
-            {
-                return -1;
-            }
-
-            for (int i = firstNull; i > position; i--)
-            {
-                _places[i] = _places[i - 1];
-            }
-
-            _places[position] = artillery;
             return position;
         }
 
@@ -69,18 +45,43 @@ namespace Artilleries
 
             var result = _places[position];
 
-            _places[position] = null;
+            _places.RemoveAt(position);
             return result;
         }
 
-        public T Get(int position)
+        public T this[int position]
         {
-            if (position < 0 || position >= Count)
+            get 
             {
-                return null;
-            }
+                if (position < 0 || position >= Count)
+                {
+                    return null;
+                }
 
-            return _places[position];
+                return _places[position];
+            }
+            set
+            {
+                if (position >= 0 && position < Count)
+                {
+                    Insert(value, position);
+                }
+            }
+        }
+
+        public IEnumerable<T> GetArtilleries()
+        {
+            foreach (var artillery in _places)
+            {
+                if (artillery != null)
+                {
+                    yield return artillery;
+                }
+                else
+                {
+                    yield break;
+                }
+            }
         }
     }
 }