fixing broken link rot

mattmakai · mattmakai · commit 048ed83e5c35 · 2021-06-02T09:54:05.000-04:00
diff --git a/content/pages/01-introduction/01-learning-programming.markdown b/content/pages/01-introduction/01-learning-programming.markdown
@@ -125,11 +125,6 @@ repositories and sites with practice problems and solutions:
 * [TeachCraft](https://teachcraft.net/) combines Minecraft with Python to
   learn coding.
 
-* [500 Data Structures and Algorithms practice problems and their solutions](https://techiedelight.quora.com/500-Data-Structures-and-Algorithms-practice-problems-and-their-solutions)
-  covers a large swath of the computer science space. It is not important
-  to know all of these algorithms and data structures but experience with
-  many of them will be greatly beneficial in becoming a better developer.
-
 
 ### First-hand advice
 These articles are written by programmers who explain how they learned to
@@ -170,10 +165,6 @@ your teaching experience:
   is an awesome resource that explains how you can use simple but fun
   drawings to teach otherwise difficult technical concepts to students.
 
-* [Teaching programming to working professionals](http://pgbovine.net/PG-Podcast-21-Trey-Hunner.htm)
-  is a video podcast with [Trey Hunter](https://twitter.com/treyhunner)
-  about his experience teaching Python to experienced professionals.
-
 * [Teach Yourself Computer Science](https://teachyourselfcs.com/) is
   intended as a self-teaching tool with many resources that are classic
   computer science textbooks. There are also nice explanations for why
diff --git a/content/pages/01-introduction/04-python-2-or-3.markdown b/content/pages/01-introduction/04-python-2-or-3.markdown
@@ -78,7 +78,7 @@ gone through the process and have advice for making it less painful.
   implementations. There is also a 
   [quick reference for writting code with Python 2 and 3 compatibility](https://wiki.python.org/moin/PortingToPy3k/BilingualQuickRef).
 
-* [Upgrading to Python 3 with Zero Downtime](https://tech.yplanapp.com/2016/08/24/upgrading-to-python-3-with-zero-downtime/)
+* [Upgrading to Python 3 with Zero Downtime](https://adamj.eu/tech/2016/08/24/upgrading-yplan-to-python-3-with-zero-downtime/)
   supplies advice on transitioning a large existing Python 2 web application 
   to Python 3. Their process involved upgrading dependencies, testing and
   deploying the new version before going back to clean up unnecessary code
diff --git a/content/pages/01-introduction/09-best-python-videos.markdown b/content/pages/01-introduction/09-best-python-videos.markdown
@@ -163,7 +163,7 @@ like [PyCon US](https://us.pycon.org/) and
   Python language.
 
 * PyCon US videos from 
-  [2020](https://www.youtube.com/c/PyCon2020/videos),
+  [2020](https://www.youtube.com/playlist?list=PL2Uw4_HvXqvbpFquYIE57BEAqkQWk-iFg),
   [2019](https://www.youtube.com/channel/UCxs2IIVXaEHHA4BtTiWZ2mQ/videos),
   [2018](https://www.youtube.com/channel/UCsX05-2sVSH7Nx3zuk3NYuQ/videos),
   [2017](https://www.youtube.com/channel/UCrJhliKNQ8g0qoE_zvL8eVg/videos),
