In my previous post, I wrote about the website includes programming problems. I aimed to emphasize the importance of careful problem text reading.
After that post, I should be more careful. However, I spent last 3 hours to find out what was wrong with my solution. I had checked every line again and again. I even implemented same functionality in different ways. I had submitted 30 times and received the 'wrong answer' every time.
I found the problem only ten minutes ago (BTW, time is about 2.25 am). Here is the problem that took 3 hours...
The problem text says "Create a new M x N image with all pixels initially colored white (O)". Yes, color white is capital letter O, not 0 (Zero). My last 3 hours and 30 submits included 0 (zero) instead O.