updating DIRECTORY.md

Author: github-actions

DIRECTORY.md

@@ -309,6 +309,7 @@
   * [Scoring Functions](https://github.com/TheAlgorithms/Python/blob/master/machine_learning/scoring_functions.py)
   * [Sequential Minimum Optimization](https://github.com/TheAlgorithms/Python/blob/master/machine_learning/sequential_minimum_optimization.py)
   * [Support Vector Machines](https://github.com/TheAlgorithms/Python/blob/master/machine_learning/support_vector_machines.py)
+  * [Word Frequency Functions](https://github.com/TheAlgorithms/Python/blob/master/machine_learning/word_frequency_functions.py)
 
 ## Maths
   * [3N Plus 1](https://github.com/TheAlgorithms/Python/blob/master/maths/3n_plus_1.py)
@@ -442,7 +443,9 @@
   * [Integeration By Simpson Approx](https://github.com/TheAlgorithms/Python/blob/master/other/integeration_by_simpson_approx.py)
   * [Largest Subarray Sum](https://github.com/TheAlgorithms/Python/blob/master/other/largest_subarray_sum.py)
   * [Least Recently Used](https://github.com/TheAlgorithms/Python/blob/master/other/least_recently_used.py)
+  * [Lfu Cache](https://github.com/TheAlgorithms/Python/blob/master/other/lfu_cache.py)
   * [Linear Congruential Generator](https://github.com/TheAlgorithms/Python/blob/master/other/linear_congruential_generator.py)
+  * [Lru Cache](https://github.com/TheAlgorithms/Python/blob/master/other/lru_cache.py)
   * [Magicdiamondpattern](https://github.com/TheAlgorithms/Python/blob/master/other/magicdiamondpattern.py)
   * [Markov Chain](https://github.com/TheAlgorithms/Python/blob/master/other/markov_chain.py)
   * [Nested Brackets](https://github.com/TheAlgorithms/Python/blob/master/other/nested_brackets.py)
@@ -566,6 +569,8 @@
     * [Sol1](https://github.com/TheAlgorithms/Python/blob/master/project_euler/problem_40/sol1.py)
   * Problem 42
     * [Solution42](https://github.com/TheAlgorithms/Python/blob/master/project_euler/problem_42/solution42.py)
+  * Problem 47
+    * [Sol1](https://github.com/TheAlgorithms/Python/blob/master/project_euler/problem_47/sol1.py)
   * Problem 48
     * [Sol1](https://github.com/TheAlgorithms/Python/blob/master/project_euler/problem_48/sol1.py)
   * Problem 52