Out of curiosity, what's the best solution to this? One thing I noticed is that every loop will pass through an entry less than 100, so you only need to remembe

Out of curiosity, what's the best solution to this? One thing I noticed is that every loop will pass through an entry less than 100, so you only need to remember the last 99 numbers below 100 when checking what's been seen-so-far. You could also precalculate or cache the answer for 1 through 100 to save rerun time. But maybe a little bit more math would reveal much better optimizations.