I posted
an article about a Project Euler problem on which I spent 41 days for a record. It was about two months after I seriously started solving PE. Now that I have just past one year mark, I have a far outstanding record: 10 months on
#233. In fact (I keep progress record in Gmail so I can precisely track) I spent ~8 months without significant progress, and spent a month on a logical progress with a lot of test & research, finally into an answer. Unfortunately it was incorrect. So I consulted Project Euler Forum (never before for this problem), which had intermediate test cases I could check my reasoning / code against. It turned out that my logic was built upon a fundamentally wrong assumption, which I could have easily confirmed with brute force code for simpler cases instead of pure reasoning. Anyway I had to re-build logic. The underlying rule was not hard to figure out if one started with concrete evidences obtained from simple brute force codes. From that point, it took me two more days to write almost new code to get a correct answer. When I hit the answer correct, the moment I waited for 10 months, I felt empty than thrilled. Maybe I was overly exhausted by this single problem. By the number of attempts that didn't work. Nevertheless I have never thought of giving up. I rather am the more attracted by other problems of similar or higher difficulty ratings (#233 has only 70% difficulty). I only wish I have weeks and months of free time. So that I can work on these problems 24/7. As infinite persistence is always ready by my side.
