- 1 current stop: learning
- 2 upcoming
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Finish after stop 5
Stop 1 of 5 · Bike shop: checking the tyres
Trick to keep in mind+3 XP
Same question asked twice? Cache it. Every question unique? Leave it alone.
Memoization only pays when a recursion calls itself with the same arguments more than once. Sketch a tiny call tree and look for two identical nodes. Splitting a list in half, halving a range or walking a tree never repeats an argument, so a cache would just add bookkeeping.
Read it once, then a question tests whether the trick stuck.