Rando Note #6

So you are telling me these are called rando notes because I cannot think up of a good title right

My first literal journal to be written lol.

Day -1

Trashed a contest. So happy about not having to get up early the following day.

Day 0

Full health spawned. Mates are making problems for the next contest on the train, but I don't have idea to that, so I spent most of the time playing chess. Honorably NATO spilled his cup noodles on ATZ.

After arrival we arrived the school and signed in. The food (I had a hamburger) was awesome.
Before sleeping I've quickly learned the basics of polymials (specifically NTT). Apart from that it's mostly about chess.

That night I fallen asleep ultra late.

Day 1

We were energetic when we woke up (I slept for about 7 hours only). Then surprisingly we found out that there's no breakfast provided so we have to search for it around. Finally I had some cup noodles. Unfortunately it wasn't my favourite flavor and the size is too small. I was still a bit hungry when we left for the contest area.

So the contest begins. Quickly I identified E as the implementation problem and L was the data structure. It was mainly about string processing. After some minutes the contest had started, there's a bunch of AC's of problem I, so we assumed it was the easiest one. It was a constructive. I quickly came up with a rough construction, which later ATZ implemented with some extra efforts. After we passed problem I, there's then a lot AC's of problem A. It looked like an ultra super greedy, but we didn't have any correct-looking ideas for some moment. I decided to implement E.

I remembered the disaster last time when I tried to implement a block covering problem and ended up in a mess. This time I tried to make every detail clear when I was implementing. There was still some dumb errors and it took us a few attempts to pass the samples. Then I got a penalty. I printed out the code for further debugging and left the computer to ATZ and pekka. They cooked, and passed problem A fast. Then I figured out that I was probably encounting with a presentation error. I stripped the spaces in EOL and decided to give another try. It passed. I looked up at the clock. 2 hours and 30 minutes has passed, and we have already done 3 problems!

The problem left were a tough. According the rankings, the only doable ones were C,F and G. We were sure that G was about number theory, but we weren't able to make any implications. I decided that F might be the easiest problem for me.

So we split up. ATZ and pekka were observing tables about problem G and I was trying to solve F. They made super abstract graphical tables regarding the answers in a small range. Just in time, the lunch arrived. There was a hamburger and a few chickens. It was relatively delicious.

Then ATZ and pekka cooked again and figured out the pattern of problem G fast. The implementation part seems to be a bit of down syndrome. ATZ and pekka couldn't implement exgcd correctly and tried lots of different tweaks for an hour and my solution for problem F was proven fake for several times, after which ATZ and pekka gave a penalty for integer overflow. Fortunately, we passed G when there was 80 minutes left.

I came up with an implementation of a correct algorithm of problem F. It looked crappy and the constant factors looked large. It was \(TC(n)=10^9\) in 4 seconds with a lot of string operations. I decided to give a try. Surprisingly, I passed it in one attempt in only 20 minutes. We had surprisingly few penalties.

The last hour was clueless. We were guessing different conclusions in problem K, only to be proven all fake. Suddenly, some team passed problem L and cheered high. Congratulations to them. From time to time we kept an eye on tybbs team. They didn't perform very well.

After the contest ends I was a bit disappoointed to be told that the ranklist is not gonna be rolled live. NATO says that he is trashed by problem L.

Me and pekka took the wrong train back to home. We panicked, but what was lucky is that the routes of two trains were identical.

Huge orz to ATZ and pekka for cooking twice.

5 problems seems decent for our level. LOL!

tpy doesn't play lavaloons anymore, sad.