added a course, a cheatsheet, a tutorial (changes made) (#9846)

* added a course, a cheatsheet, a tutorial

* removed errors

* updated file according to requested changes.

courses/free-courses-en.md

@@ -263,7 +263,7 @@
 * [AutoIt Tutorials](https://www.youtube.com/playlist?list=PL1DCD109B801D0DE6) - 403forbidden403
 
 
-### Ballerina 
+### Ballerina
 
 * [[Introductory]Integration with Ballerina](https://www.youtube.com/playlist?list=PL7JOecNWBb0KTB3vBz9Dkpc676HzhEDkN) - Shafreen Anfer
 * [Ballerina Code to Cloud](https://www.youtube.com/playlist?list=PL7JOecNWBb0I1YcKwNEyMewhiSvwhM4in) - Anjana Supun
@@ -311,7 +311,7 @@
 * [C Programming Tutorial](https://www.youtube.com/playlist?list=PL_RGaFnxSHWoGzOXqtKeM71OLpvZbuU0P)
 * [C Programming Tutorial for Beginners](https://www.youtube.com/watch?v=KJgsSFOSQv0) - Mike Dane (freeCodeCamp)
 * [Learn C Programming](https://www.programiz.com/c-programming) - Programiz (HTML)
-* [Programming in C](https://www.youtube.com/playlist?list=PLdo5W4Nhv31a8UcMN9-35ghv8qyFWD9_S) - Jenny's lectures CS/IT NET&JRF 
+* [Programming in C](https://www.youtube.com/playlist?list=PLdo5W4Nhv31a8UcMN9-35ghv8qyFWD9_S) - Jenny's lectures CS/IT NET&JRF
 * [The Arduino Platform and C Programming](https://www.coursera.org/learn/arduino-platform)
 
 
@@ -469,7 +469,7 @@
 * [Data Science Methodology](https://cognitiveclass.ai/courses/data-science-methodology-2) - CognitiveClass.ai
 * [Data Visualization](https://www.kaggle.com/learn/data-visualization) - Alexis Cook (Kaggle)
 * [Datavis 2020](https://www.youtube.com/playlist?list=PL9yYRbwpkykuK6LSMLH3bAaPpXaDUXcLV) - Curran Kelleher
-* [Hadoop Tutorial for Beginners](https://www.youtube.com/playlist?list=PLlgLmuG_KgbasW0lpInSAIxYd2vqAEPit) - Great Learning 
+* [Hadoop Tutorial for Beginners](https://www.youtube.com/playlist?list=PLlgLmuG_KgbasW0lpInSAIxYd2vqAEPit) - Great Learning
 * [Hive Tutorial](https://www.youtube.com/watch?v=MLDcapDQba4) - Great Learning
 * [IBM Data Science Professional Certificate](https://www.coursera.org/professional-certificates/ibm-data-science) (Coursera)
 * [Intro to Data Analysis](https://www.udacity.com/course/intro-to-data-analysis--ud170) - Udacity
@@ -544,6 +544,8 @@
 * [Practical Deep Learning For Coders taught](http://www.fast.ai) - Jeremy Howard
 * [Practical Deep Learning for Coders, v3 (using fastai library)](https://course.fast.ai)
 * [Self-Paced Courses for Deep Learning](https://developer.nvidia.com/deep-learning-courses)
+* [Stanford CS 224N: Natural Language Processing with Deep Learning](https://www.youtube.com/playlist?list=PLoROMvodv4rOSH4v6133s9LFPRHjEmbmJ) (Stanford Online)
+* [Stanford CS230: Deep Learning](https://www.youtube.com/playlist?list=PLoROMvodv4rOABXSygHTsbvUz4G_YQhOb) (Stanford Online)
 * [Unsupervised Feature Learning and Deep Learning](http://deeplearning.stanford.edu/tutorial)
 * [What is Deep Learning](https://www.udacity.com/course/deep-learning--ud730) (Udacity)
 
@@ -1094,7 +1096,7 @@
 ### Linux
 
 * [Fundamentals of Red Hat Enterprise Linux](https://www.edx.org/course/fundamentals-of-red-hat-enterprise-linux) - Chris Caillouet (edX)
-* [IIEC RISE 1.0 RHCSA8 and Python3](https://www.youtube.com/playlist?list=PLAi9X1uG6jZ2b1mUmrUcc_aEoc8tfss8e) - Vimal Daga 
+* [IIEC RISE 1.0 RHCSA8 and Python3](https://www.youtube.com/playlist?list=PLAi9X1uG6jZ2b1mUmrUcc_aEoc8tfss8e) - Vimal Daga
 * [Introduction To Linux](https://www.edx.org/course/introduction-to-linux/) - The Linux Foundation (edx)
 * [Linux Administration Tutorial Videos](https://www.youtube.com/playlist?list=PL9ooVrP1hQOH3SvcgkC4Qv2cyCebvs0Ik) - edureka!
 * [Linux Command Line](https://www.udemy.com/course/command-line/) - Adam Eubankas (Udemy)
@@ -1190,7 +1192,7 @@
 ### Networking
 
 * [CompTIA N10-008 Network+ Training Course](https://www.youtube.com/playlist?list=PLG49S3nxzAnlCJiCrOYuRYb6cne864a7G) - Professor Messer
-* [Computer Networking: A Top-Down Approach 8th edition](http://gaia.cs.umass.edu/kurose_ross/online_lectures.htm) - Jim Kurose, Keith Ross 
+* [Computer Networking: A Top-Down Approach 8th edition](http://gaia.cs.umass.edu/kurose_ross/online_lectures.htm) - Jim Kurose, Keith Ross
 * [Computer Networking Course](https://www.youtube.com/watch?v=qiQR5rTSshw) - Brian Farrell (FreeCodeCamp.org)
 * [Computer Networking Full Course - OSI Model Deep Dive with Real Life Examples](https://www.youtube.com/watch?v=IPvYjXCsTg8) - Kunal Kushwaha
 * [Computer Networks 5e](https://media.pearsoncmg.com/ph/streaming/esm/tanenbaum5e_videonotes/tanenbaum_videoNotes.html) - Andrew Tanenbaum, David Wetherall (Pearson)
@@ -1562,4 +1564,3 @@
 ### YAML
 
 * [Complete YAML Course - Beginner to Advanced for DevOps and more!](https://www.youtube.com/watch?v=IA90BTozdow) - Kunal Kushwaha
-

more/free-programming-cheatsheets.md

@@ -122,6 +122,7 @@
 
 * [Algorithms and Data Structures Cheatsheet](https://algs4.cs.princeton.edu/cheatsheet/)
 * [An Executable Data Structures Cheat Sheet for Interviews](https://algodaily.com/lessons/an-executable-data-structures-cheat-sheet)
+* [Big-O Cheat Sheet](http://bigocheatsheet.com)
 * [Big O Notation Cheat Sheet](https://algodaily.com/lessons/big-o-notation-cheat-sheet)
 * [Data Structures and Algorithms Cheat Sheet - Cheatography](https://cheatography.com/burcuco/cheat-sheets/data-structures-and-algorithms/)
 * [Data structures and algorithms study cheatsheets for coding interviews](https://www.techinterviewhandbook.org/algorithms/study-cheatsheet/)
@@ -177,7 +178,7 @@
 ### GraphQL
 
 * [GraphQL Cheat Sheet](https://licor.me/post/graphql) - Chuanrong Li (HTML)
-* [GraphQL Cheat Sheet](https://cheatsheetseries.owasp.org/cheatsheets/GraphQL_Cheat_Sheet.html) - Jim Manico, Jakub Maćkowski (HTML) 
+* [GraphQL Cheat Sheet](https://cheatsheetseries.owasp.org/cheatsheets/GraphQL_Cheat_Sheet.html) - Jim Manico, Jakub Maćkowski (HTML)
 * [GraphQL Cheat Sheet](https://simplecheatsheet.com/tag/graphql-cheat-sheet) - Simple Cheat Sheet (HTML)
 * [GraphQL Cheatsheet](https://devhints.io/graphql) - devhints, Rico Santa Cruz (HTML)
 

more/free-programming-interactive-tutorials-en.md

@@ -385,7 +385,7 @@
 
 ### Jupyter
 
-* [Data-Quest](https://www.dataquest.io/blog/jupyter-notebook-tutorial/) - Benjamin Pryke 
+* [Data-Quest](https://www.dataquest.io/blog/jupyter-notebook-tutorial/) - Benjamin Pryke
 * [Jupyter](https://docs.jupyter.org)
 * [Learn Jupyter](https://jupyter-notebook.readthedocs.io) - Read the Docs
 
@@ -442,6 +442,7 @@
 * [SQL Tutorial](https://www.w3schools.com/sql) - W3Schools
 * [SQL Tutorial](https://www.scaler.com/topics/sql/) - Scaler Topics
 * [SQLBolt](http://sqlbolt.com)
+* [SQLZoo](https://sqlzoo.net/wiki/SQL_Tutorial)
 
 
 ### XML