Supplemental videos and tools to accompany the Day 1 recursion notes. Use at your own risk! I did not check every link.

Videos

Resource Description
Coding with John - Recursion in Java ~12 min. Clean Java examples including countdown/countup comparison.
CS Dojo - Introduction to Recursion ~8 min. Good call stack visualization.
mycodeschool - Recursion playlist Thorough explanations, good for rewatching.
Computerphile - What on Earth is Recursion? Conceptual/fun take on why recursion matters.

Interactive Tools

Resource Description
Python Tutor (supports Java) Step through recursive code and watch the call stack build/unwind. Paste your own code.
USFCA Algorithm Visualizations Includes recursion trees — great for showing why naive Fibonacci explodes.

AP CSA Practice

Resource Description
AP Classroom Unit 10 videos and practice questions in AP exam style.
CSAwesome (Runestone) Free textbook with embedded practice problems.

Tips for Students

  • Use Python Tutor to visualize any recursive function you’re confused about
  • Trace bottom-up — start from the base case and work back
  • Watch for the pattern: print before call = forward order, print after call = reverse order