Implemented Splay Tree Data Structure (#168)

* Added Disjoint Sets Data structure

* Moved DisjointSetTest.php to  tests/DataStructures

* Update DataStructures/DisjointSets/DisjointSet.php

Co-authored-by: Brandon Johnson <bbj1979@gmail.com>

* Update DataStructures/DisjointSets/DisjointSetNode.php

Co-authored-by: Brandon Johnson <bbj1979@gmail.com>

* Update DataStructures/DisjointSets/DisjointSetNode.php

Co-authored-by: Brandon Johnson <bbj1979@gmail.com>

* Update tests/DataStructures/DisjointSetTest.php

Co-authored-by: Brandon Johnson <bbj1979@gmail.com>

* Update tests/DataStructures/DisjointSetTest.php

Co-authored-by: Brandon Johnson <bbj1979@gmail.com>

* Update tests/DataStructures/DisjointSetTest.php

Co-authored-by: Brandon Johnson <bbj1979@gmail.com>

* Considered PHPCS remarks. Unit Testing is now working.

* Remove data type mixed. Considered annotations for php7.4.

* Remove data type mixed. Considered annotations for php7.4.

* updating DIRECTORY.md

* Implemented Trie DataStructure

* Added Trie to DIRECTORY.md

* updating DIRECTORY.md

* Implemented AVLTree DataStructure

* updating DIRECTORY.md

* Implemented AVLTree DataStructure

* Implemented SegmentTreeNode.php

* Implementing SegmentTree

* Implementing SegmentTree with updateTree

* Implementing SegmentTree with rangeUpdateTree

* Implementing SegmentTree with query and queryTree

* Added serializing and deserializing of the SegmentTree

* Adding unit tests SegmentTree implementation

* Added unit tests for SegmentTree updates and range updates

* considering PHPCS for Added unit tests for SegmentTree updates and range updates

* Added unit tests for SegmentTree serialization/deserialization and array updates reflections

* Added unit tests for SegmentTree  Edge Cases

* Added unit tests for SegmentTree Exceptions (OutOfBoundsException, InvalidArgumentException)

* Added SegmentTree to DIRECTORY.md

* Implemented Segment Tree Data Structure

* updating DIRECTORY.md

* Added some comments to my files in: #160, #162, #163, #166. Implemented Segment Tree Data Structure.

* Added some comments to my files in: #160, #162, #163, #166. Implemented Segment Tree Data Structure.

* Added comments time complexity for query(), update() and buildTree()

* Implemented Splay Tree Data Structure

* Update tests/DataStructures/SplayTreeTest.php

Co-authored-by: Brandon Johnson <bbj1979@gmail.com>

---------

Co-authored-by: Brandon Johnson <bbj1979@gmail.com>
Co-authored-by: Ramy-Badr-Ahmed <Ramy-Badr-Ahmed@users.noreply.github.com>

DIRECTORY.md

@@ -31,6 +31,10 @@
     * [Segmenttree](./DataStructures/SegmentTree/SegmentTree.php)
     * [Segmenttreenode](./DataStructures/SegmentTree/SegmentTreeNode.php)
   * [Singlylinkedlist](./DataStructures/SinglyLinkedList.php)
+  * Splaytree
+    * [Splaytree](./DataStructures/SplayTree/SplayTree.php)
+    * [Splaytreenode](./DataStructures/SplayTree/SplayTreeNode.php)
+    * [Splaytreerotations](./DataStructures/SplayTree/SplayTreeRotations.php)
   * [Stack](./DataStructures/Stack.php)
   * Trie
     * [Trie](./DataStructures/Trie/Trie.php)
@@ -132,6 +136,7 @@
     * [Queuetest](./tests/DataStructures/QueueTest.php)
     * [Segmenttreetest](./tests/DataStructures/SegmentTreeTest.php)
     * [Singlylinkedlisttest](./tests/DataStructures/SinglyLinkedListTest.php)
+    * [Splaytreetest](./tests/DataStructures/SplayTreeTest.php)
     * [Stacktest](./tests/DataStructures/StackTest.php)
     * [Trietest](./tests/DataStructures/TrieTest.php)
   * Graphs