Improvements

Author: NelsonBN

src/4.ResizableHashTable/Program.cs

@@ -71,14 +71,19 @@ public void Add(TKey key, TValue value)
         else
         {
             var current = _buckets[index];
-            while(current.Next is not null)
+            if(current.Key.Equals(key))
             {
-                current = current.Next;
+                throw new InvalidOperationException("Key already exists");
             }
 
-            if(current.Key.Equals(key))
+            while(current.Next is not null)
             {
-                throw new InvalidOperationException("Key already exists");
+                current = current.Next;
+
+                if(current.Key.Equals(key))
+                {
+                    throw new InvalidOperationException("Key already exists");
+                }
             }
 
             current.Next = node;