diff --git a/.travis.yml b/.travis.yml
index 3f1343bfa..bda0fc31c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,26 +4,21 @@ language: python
 python: 3.8
 cache: pip
 before_install: pip install --upgrade pip setuptools six
-install: pip install black flake8
 jobs:
   include:
     - name: Build
-      before_script:
-        - black --check . || true
-        - flake8 --ignore=E203,W503 --max-complexity=25 --max-line-length=88 --statistics --count .
-        - scripts/validate_filenames.py  # no uppercase, no spaces, in a directory
-        - pip install -r requirements.txt  # fast fail on black, flake8, validate_filenames
+      install: pip install pytest-cov -r requirements.txt
       script:
-        - mypy --ignore-missing-imports . || true  # https://github.com/python/mypy/issues/7907
         - pytest --doctest-modules --ignore=project_euler/ --durations=10 --cov-report=term-missing:skip-covered --cov=. .
     - name: Project Euler
-      before_script:
+      install:
         - pip install pytest-cov pytest-subtests
+      before_script:
         - pytest --tb=no --no-summary --capture=no project_euler/validate_solutions.py || true  # fail fast on wrong solution
       script:
         - pytest --doctest-modules --durations=10 --cov-report=term-missing:skip-covered --cov=project_euler/ project_euler/
 after_success:
   - scripts/build_directory_md.py 2>&1 | tee DIRECTORY.md
 notifications:
-    webhooks: https://www.travisbuddy.com/
-    on_success: never
+  webhooks: https://www.travisbuddy.com/
+  on_success: never
diff --git a/DIRECTORY.md b/DIRECTORY.md
index 3227711c7..37eaadb89 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -190,6 +190,8 @@
 ## Divide And Conquer
   * [Closest Pair Of Points](https://github.com/TheAlgorithms/Python/blob/master/divide_and_conquer/closest_pair_of_points.py)
   * [Convex Hull](https://github.com/TheAlgorithms/Python/blob/master/divide_and_conquer/convex_hull.py)
+  * [Heaps Algorithm](https://github.com/TheAlgorithms/Python/blob/master/divide_and_conquer/heaps_algorithm.py)
+  * [Heaps Algorithm Iterative](https://github.com/TheAlgorithms/Python/blob/master/divide_and_conquer/heaps_algorithm_iterative.py)
   * [Inversions](https://github.com/TheAlgorithms/Python/blob/master/divide_and_conquer/inversions.py)
   * [Max Subarray Sum](https://github.com/TheAlgorithms/Python/blob/master/divide_and_conquer/max_subarray_sum.py)
   * [Mergesort](https://github.com/TheAlgorithms/Python/blob/master/divide_and_conquer/mergesort.py)
@@ -244,6 +246,7 @@
 
 ## Graphics
   * [Bezier Curve](https://github.com/TheAlgorithms/Python/blob/master/graphics/bezier_curve.py)
+  * [Vector3 For 2D Rendering](https://github.com/TheAlgorithms/Python/blob/master/graphics/vector3_for_2d_rendering.py)
 
 ## Graphs
   * [A Star](https://github.com/TheAlgorithms/Python/blob/master/graphs/a_star.py)
@@ -319,6 +322,7 @@
   * [Data Transformations](https://github.com/TheAlgorithms/Python/blob/master/machine_learning/data_transformations.py)
   * [Decision Tree](https://github.com/TheAlgorithms/Python/blob/master/machine_learning/decision_tree.py)
   * [Gaussian Naive Bayes](https://github.com/TheAlgorithms/Python/blob/master/machine_learning/gaussian_naive_bayes.py)
+  * [Gradient Boosting Regressor](https://github.com/TheAlgorithms/Python/blob/master/machine_learning/gradient_boosting_regressor.py)
   * [Gradient Descent](https://github.com/TheAlgorithms/Python/blob/master/machine_learning/gradient_descent.py)
   * [K Means Clust](https://github.com/TheAlgorithms/Python/blob/master/machine_learning/k_means_clust.py)
   * [K Nearest Neighbours](https://github.com/TheAlgorithms/Python/blob/master/machine_learning/k_nearest_neighbours.py)
@@ -650,6 +654,7 @@
     * [Sol1](https://github.com/TheAlgorithms/Python/blob/master/project_euler/problem_97/sol1.py)
   * Problem 99
     * [Sol1](https://github.com/TheAlgorithms/Python/blob/master/project_euler/problem_99/sol1.py)
+  * [Validate Solutions](https://github.com/TheAlgorithms/Python/blob/master/project_euler/validate_solutions.py)
 
 ## Scheduling
   * [First Come First Served](https://github.com/TheAlgorithms/Python/blob/master/scheduling/first_come_first_served.py)
@@ -753,6 +758,7 @@
   * [Fetch Jobs](https://github.com/TheAlgorithms/Python/blob/master/web_programming/fetch_jobs.py)
   * [Get Imdb Top 250 Movies Csv](https://github.com/TheAlgorithms/Python/blob/master/web_programming/get_imdb_top_250_movies_csv.py)
   * [Get Imdbtop](https://github.com/TheAlgorithms/Python/blob/master/web_programming/get_imdbtop.py)
+  * [Instagram Crawler](https://github.com/TheAlgorithms/Python/blob/master/web_programming/instagram_crawler.py)
   * [Recaptcha Verification](https://github.com/TheAlgorithms/Python/blob/master/web_programming/recaptcha_verification.py)
   * [Slack Message](https://github.com/TheAlgorithms/Python/blob/master/web_programming/slack_message.py)
   * [World Covid19 Stats](https://github.com/TheAlgorithms/Python/blob/master/web_programming/world_covid19_stats.py)
diff --git a/requirements.txt b/requirements.txt
index cb38123dc..31dc586c2 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,18 +1,12 @@
 beautifulsoup4
-black
 fake_useragent
-flake8
 keras
 lxml
 matplotlib
-mypy
 numpy
 opencv-python
 pandas
 pillow
-pre-commit
-pytest
-pytest-cov
 requests
 scikit-fuzzy
 sklearn