It was a little frustrating that the main edge case that caught everyone didn't blow up my implementation, and going row by row of the 1000 line input it wasn't immediately obvious where it was going wrong (I'm not sure how far down I would've had to go to find the first time it hits this edge case, I just ended up checking the reddit for hints).
I really do think things like this should at least be hinted in the text to save a little frustration; I'm not trying to be the best on the leaderboard, I'm just doing these in the morning before work for a little fun.
I only found my edge case (and dumb implementation mistake, I guess) by forking a "working solution" from someone else, outputting their solution for each line, then diffing that with a similar output from mine. It took me a lot of debugging and troubleshooting.
Once I diffed it against a working output it was clear and solved within minutes.
I really do think things like this should at least be hinted in the text to save a little frustration; I'm not trying to be the best on the leaderboard, I'm just doing these in the morning before work for a little fun.