Killing Fibonacci
summary
Builds a Ruby TDD pipeline: a four fib methods Fibonacci calculator (recursion, iteration, array, matrix) and an injected stock‑price retracement predictor that computes retracement = (high − low) × iterations / fib(iterations). Measures show recursion is unusable, iteration ≈2s for fib(250k), array ≈5s, matrix <1s and fib of a million 86,784 digits computes in ~0.5s. Tests drive refactors, reveal the domain vs implementation split, and the predictor reproduces plausible Apple retracement numbers (≈426, 452).
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chapters (14)
- 0:00Fibonacci journey intro
- 1:55Stock picker app challenge
- 3:38Courage to conquer fear
- 4:41Baby steps for peace
- 6:52Do the minimum
- 10:01Stay focused minimize red time
- 13:15Listen to your tests
- 15:00Know your domain
- 16:23Refactor from green
- 17:05Behavior over implementation
- 18:47Tenacity stick-to-it-ness
- 24:22Code versus software
- 31:28Live demo results
- 33:1310 lessons summary
