updating DIRECTORY.md

Author: AHuzail

DIRECTORY.md

@@ -22,6 +22,7 @@
   * [Rat In Maze](backtracking/rat_in_maze.py)
   * [Sudoku](backtracking/sudoku.py)
   * [Sum Of Subsets](backtracking/sum_of_subsets.py)
+  * [Word Break](backtracking/word_break.py)
   * [Word Ladder](backtracking/word_ladder.py)
   * [Word Search](backtracking/word_search.py)
 
@@ -99,6 +100,7 @@
   * [Elgamal Key Generator](ciphers/elgamal_key_generator.py)
   * [Enigma Machine2](ciphers/enigma_machine2.py)
   * [Fractionated Morse Cipher](ciphers/fractionated_morse_cipher.py)
+  * [Gronsfeld Cipher](ciphers/gronsfeld_cipher.py)
   * [Hill Cipher](ciphers/hill_cipher.py)
   * [Mixed Keyword Cypher](ciphers/mixed_keyword_cypher.py)
   * [Mono Alphabetic Ciphers](ciphers/mono_alphabetic_ciphers.py)
@@ -211,6 +213,7 @@
     * [Lazy Segment Tree](data_structures/binary_tree/lazy_segment_tree.py)
     * [Lowest Common Ancestor](data_structures/binary_tree/lowest_common_ancestor.py)
     * [Maximum Fenwick Tree](data_structures/binary_tree/maximum_fenwick_tree.py)
+    * [Maximum Sum Bst](data_structures/binary_tree/maximum_sum_bst.py)
     * [Merge Two Binary Trees](data_structures/binary_tree/merge_two_binary_trees.py)
     * [Mirror Binary Tree](data_structures/binary_tree/mirror_binary_tree.py)
     * [Non Recursive Segment Tree](data_structures/binary_tree/non_recursive_segment_tree.py)
@@ -284,6 +287,7 @@
     * [Dijkstras Two Stack Algorithm](data_structures/stacks/dijkstras_two_stack_algorithm.py)
     * [Infix To Postfix Conversion](data_structures/stacks/infix_to_postfix_conversion.py)
     * [Infix To Prefix Conversion](data_structures/stacks/infix_to_prefix_conversion.py)
+    * [Lexicographical Numbers](data_structures/stacks/lexicographical_numbers.py)
     * [Next Greater Element](data_structures/stacks/next_greater_element.py)
     * [Postfix Evaluation](data_structures/stacks/postfix_evaluation.py)
     * [Prefix Evaluation](data_structures/stacks/prefix_evaluation.py)
@@ -820,6 +824,7 @@
     * [Softplus](neural_network/activation_functions/softplus.py)
     * [Squareplus](neural_network/activation_functions/squareplus.py)
     * [Swish](neural_network/activation_functions/swish.py)
+  * [Artificial Neural Network](neural_network/artificial_neural_network.py)
   * [Back Propagation Neural Network](neural_network/back_propagation_neural_network.py)
   * [Convolution Neural Network](neural_network/convolution_neural_network.py)
   * [Input Data](neural_network/input_data.py)
@@ -1201,6 +1206,7 @@
   * [Binary Tree Traversal](searches/binary_tree_traversal.py)
   * [Double Linear Search](searches/double_linear_search.py)
   * [Double Linear Search Recursion](searches/double_linear_search_recursion.py)
+  * [Exponential Search](searches/exponential_search.py)
   * [Fibonacci Search](searches/fibonacci_search.py)
   * [Hill Climbing](searches/hill_climbing.py)
   * [Interpolation Search](searches/interpolation_search.py)