Sudoku Challenge

Today my school had this sudoku challenge set up infront of the library and anyone who wanted to try it out could give it a shot. I thought it'd be interesting to try it out myself. The previous night I was rattling my brains out trying the very difficult puzzles in my sudoku book. It took me an hour for the first puzzle. After that, it became easy and I managed to solve one in 20 minutes. So today I felt ready for the challenge, thinking what level they would be giving us. To my surprise, it was not that difficult. In a way, it was easier than my normal leveled puzzles. So I was going at a nice slow pace and suddenly I would find the key numbers and start filling in the rest at a really fast pace. And then I'll come to a stop with the last 10 or so numbers. This was already at the 20 minute mark. I was quite surprised with my timing. I knew that I could finish it withing 25 minutes, but then it happened. For some reason, I made one of the worst mistakes that I could have ever made. I wasn't able to see that one of the crucial numbers placed in a certain box could have had two possiblities. Because of this, I wasted lots of precious time. After making the mistake without realizing, I began to finish up the puzzle till I suddenly saw the error. This was about the 25 minute mark. I quickly tried to re-trace my steps, but couldn't as I had filled them up in a hurry. So I decided to erase the whole thing. It couldn't be helped. Luckily, I managed to fill everything that was correct back into it's place within 5 minutes and figured out my mistake. The puzzle was finished in about 30 minutes or so. It could have been much faster. But oh well. I heard the longest was about an hour. There probably is someone who did much better than me.

Life Goes On.