Revert "Fixed Issue aalhour#139 A new SkipList<int> contains 0"

This reverts commit 9cab153.

Author: Gutsonok

DataStructures/Lists/SkipList.cs

@@ -194,20 +194,15 @@ public bool Remove(T item, out T deleted)
         /// </summary>
         public bool Contains(T item)
         {
-            return Find(item, out var _);
+            T itemOut;
+            return Find(item, out itemOut);
         }
 
         /// <summary>
         /// Look for an element and return it if found
         /// </summary>
         public bool Find(T item, out T result)
         {
-            result = default;
-            if(IsEmpty)
-            {
-                return false;
-            }
-
             var current = _firstNode;
 
             // Walk after all the nodes that have values less than the node we are looking for
@@ -224,6 +219,7 @@ public bool Find(T item, out T result)
                 return true;
             }
 
+            result = default(T);
             return false;
         }
 

UnitTest/DataStructuresTests/SkipListTest.cs

@@ -6,16 +6,6 @@ namespace UnitTest.DataStructuresTests
 {
     public static class SkipListTest
     {
-        [Fact]
-        public static void EmptyList()
-        {
-            var skipList = new SkipList<int>();
-
-            Assert.True(skipList.Count == 0);
-            Assert.True(skipList.IsEmpty);
-            Assert.DoesNotContain(0, skipList);
-        }
-
         [Fact]
         public static void AddOneElement()
         {