Just several hours ago, JSOI2017(the selection contest in my province) ended, and I ended up with rank 5. Finally, I could go to NOI(Chinese National Olympiad of Informatics, more details can be found here), which will be held in July. Although rank 5 is pretty good, there's still a wide gap between top 4 and me(congrats to the top 4 who may get a 5-point bonus in NOI). This means I have to learn more and train harder, so here comes the post. In this post, I'm gonna record my daily training and contests during the last two and a half months. I hope keeping updating will push me to train harder and also improve my English in the same time. The problems mentioned here may be easier than those mentioned in matthew99's and Petr's blog, but I'll do my best to make this post great. Hope you may like it. :)
Codeforces Round #411 will start in less than one hour. I'll make my first record after it. Wish everyone good luck.
My performance in the contest was a complete flop. I was too sleepy to code problem C and D, though they were not too difficult. I was exhausted after the two-day provincial-team-selecting contest. Maybe all I need now is just a good rest. I will solve the problems left in the contest after that and share with you later.
I solved problem B of Petr Mitrichev Contest 1. The problem is not too difficult. The key is that if we know the value of A(1, j) and A(i, 1), then we can calculate all A(i, j). Then the problem becomes whether there exists some values of A(1, j) and A(i, 1) such that all A(i, j) is between 0 and 1. For two elements A(i, 1) and A(1, j), we have some limits that it's impossible for A(i, 1) = x and A(1, j) = y simultaneously. So the problem becomes a 2-SAT.
In the evening, I took part in Atcoder Grand Contest 014, which was another flop to me. The problems are a little bit easier than usual, and there was a data structure problem. However, I still just solved 4 problems. I couldn't focus when coding, and as a result I made some stupid mistakes when coding C and D. I tried to solve problem E after that, and my performance on E was just shit. After having an idea, I hurried to code. Still, I made a lot of mistakes when coding, and couldn't accept it in time. After the contest, I tried a lot of times before accepting it. I found that both my ideas and implementation were wrong. As a Chinese OIer, I couldn't solve this data structure problem. What a shame!
After JSOI and AGC014, I noticed that I'm now having a big problem of coding. I always made some small mistakes such as typo when coding, and often need a lot of debugging to get accept. I should try to focus on my code when coding, and train more problems which are difficult to implement. Have you once had the same problem? And how do you avoid making stupid mistakes when coding?