Change, this is my summary of this year's NOIP. From the site selection of the Tianjin competition area to the new campus, to the CCF update of the "master machine" that has been criticized by countless players for a long time, it can be seen that NOIP continues to improve and is increasingly valued.Don't talk nonsense, talk about the idea of this exam.
The first question is to pave the road. A simple greed is to hit a tree array at random for 30min A to cut off the next question (actually, the time is longer than 30min).
I saw the second question, "Fuck" and "Maths", which was the enhanced version of Xiao Kai's doubts last year.However, a simple analysis shows that if a number can be represented by other numbers, it must be useless, otherwise it must be useful ("obviously"). After playing with several groups of examples, we found that the idea was correct, and then we played a sieve, and cut the next question after one hour.The sieve here has a pit, just like the Euler sieve, and a mark must be made, otherwise the complexity cannot be guaranteed.
Then go to the toiletTake a breath of fresh air, about 2.5 hours later.
Look at the third question. After reading the question twice, I found it was a tree dynamic planning. Unfortunately, my tree dynamic planning was learned last week. Knock out the violence, write a pair of photos, test several groups of test data, and hand in the paper.
The topic of Day 1 this year seems to have hit the Internet, but unfortunately I haven't done it (zg dalao lost 300 questions%%% in two months).
Day 2
After reading the question once, I found that the data of the first question is particularly magical. It is a single ring tree. Consider breaking the upper edge of the ring and then enumerating to do it. This complexity has already been O (n ^ 2), but it also requires the least. So the idea on the examination room is to arrange the order every time,So that's it. I didn't think about it.Fortunately, I was lucky enough to get stuck with my "excellent" card skills.To be specific, vector is used to store all edges
The second question, "Fuck", is also a math question. However, because of my high heart, I made a mistake that I must not make in the exam room, that is, hard resistance. The fact proved that if I had not been lucky enough, T3 was released in the last 30 minutes, otherwise it would be cool. This question took me a full hour, but finally I decided to change the question to reduce losses,After the last question was typed out, I came back to find several groups of idiot data. I typed a table and handed it in. Finally, I only deducted 5 points from the basic violence score, thanks to CCF's weak data
Third question, is this NOI PlusNo, I knocked a violent hand in.
summary
Generally speaking, the experience is OK, but I made a mistake before and this time again. Time planning is really very, very important!
In addition, I feel that my code style in this competition has suffered a lot, because the code readability principle I have always adhered to has led to my code being more than twice as long as others. This may need to be changed. After all, it is a competitive competition, not a long-term maintenance project.
394. The score of nearly 400 points is enough for my one-year effort. I am very satisfied.
NOI 2019 See you next year!
The picture shows NOIP 2018 Tianjin Examination Hall, Beiyang Garden Campus of Tianjin University.
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