[2025 Day 09 (Part 2)] The day 9 difficulty spike quantified
Day 9 really kicked my butt, it took around 5x longer than Day 8 in terms of effort, more than 2x the lines of code of any previous puzzle this year, and even after putting a lot of work into optimising it, still with a runtime nearly twice as slow as the next slowest day.
(Speaking of which, I really should go back and optimise day 3 a bit more, hey)
I haven't got solid numbers on how much time effort I put into each solution (that's why it's not on the graph) but all the other puzzles were definitely <1h, and Day 9 was at least 4h, probably dipping into the 5h range.
Posted Dec 10, 2025, 3:04 AM UTC
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