updating DIRECTORY.md

Author: cclauss

DIRECTORY.md

@@ -251,6 +251,7 @@
     * [Basic Binary Tree](data_structures/binary_tree/basic_binary_tree.py)
     * [Binary Search Tree](data_structures/binary_tree/binary_search_tree.py)
     * [Binary Search Tree Recursive](data_structures/binary_tree/binary_search_tree_recursive.py)
+    * [Binary Tree Maximum Path Sum](data_structures/binary_tree/binary_tree_maximum_path_sum.py)
     * [Binary Tree Mirror](data_structures/binary_tree/binary_tree_mirror.py)
     * [Binary Tree Node Sum](data_structures/binary_tree/binary_tree_node_sum.py)
     * [Binary Tree Path Sum](data_structures/binary_tree/binary_tree_path_sum.py)
@@ -876,6 +877,7 @@
   * [Test Factorial](maths/test_factorial.py)
   * [Test Prime Check](maths/test_prime_check.py)
   * [Three Sum](maths/three_sum.py)
+  * [Tonelli Shanks](maths/tonelli_shanks.py)
   * [Trailing Zeroes](maths/trailing_zeroes.py)
   * [Trapezoidal Rule](maths/trapezoidal_rule.py)
   * [Triplet Sum](maths/triplet_sum.py)