Preface ： The journey is not long , If you can pass . There are not many yards , No insect, no spirit . Si is Xinjing , But I burst zero . Segment maintenance is fast , The tree jumps frequently . Number theory remainder system , Graph theory forward star . Countless competing reasoning , Nothing competes for labor . Big brother building leader , Super Yao Qizhi , Divine cloud ： You are too strong .
morning 5：00 Woke up , I can't sleep at all
5：30, Toss and turn in bed and can't sleep , I had to get up and take a bath
8：30 Start the game , Not in good shape , A little sleepy
T1
A brief introduction to the topic ： seek \(l,r\) Between modules \(n\) The maximum number of .
Just saw this problem , I didn't think so much , Call directly on the computer , Using a double loop nesting , After typing, look at the question carefully , Only then discovered
This is a math problem
Take a look at the data range \(r-l≤10^9\)
Um. , Must be \(O(1)\) Of course. .
consider , If \(r-l≥n\) The output \(n-1\)n
otherwise , Consider again \(l,r\) First mold \(n\) , Write it down as \(L,R\).
If \(R<L\) Obviously the maximum is \(n-1\).
Otherwise, \(R\) individual .
This question obviously shouldn't be wrong
T2
data structure , Inquire about + modify
In a stupid way
modify \(O(1)\), Inquire about \(O(nlogn)\)
Modify direct logarithmic modification , For inquiry 2 All over sort+1 A binary search
I spend most of my time looking for two points （ Finally, I found a wrong letter ）
As a result, there is not much time behind
direct luogu Run up TLE
T3
Seeing a large string of words, I feel that this problem is not simple , Glancing at the title a few times , To do T4 了
Look at it after you come back , Discovery is an extremely disgusting thing
This is the big simulation
FIAL and OK Everything was very good , The key is ERR, For a long time
After the adjustment, I found that it was always wrong , At this time, there is still about 5,6 minute
No way out , You can only delete the typing table and leave it to fate
T4
Read the title a few times , Hit a violent , Time complexity .... Quite high
I've been thinking about how to optimize , Suddenly I thought of the linked list ( But I forgot how to play )
So I put it there , No matter the , Go fight T3
It's over T3 after , The exam is almost over , result , I am here T3 There are cheap hands (vscode sequelae ) Press one F5, I didn't save it T4......
The mentality at that time has collapsed , Don't want to move anything , The hard fought violence is gone , There are only three codes left （ There is also a watch ）, It must be too late to hit again , I had to type another watch at last ......
After leaving the examination room, the whole person was stupid
summary
There are problems in the mentality and state of this exam （ Almost fell asleep in the bathroom ）
This scene CSP It was the first game I participated in OI match , Maybe I care too much
The whole heart is highly nervous , Especially when the program is gone ......
however , Meditate in your heart ： At least I passed the preliminary round , Many people haven't even passed the preliminaries
Just try your best
Pay more attention in the future
Calm down , Welcome the game with the best attitude
come on. ！
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