Hello, Codeforces!

This week we had the Brazilian Selection for International Informatics Competitions! Soon, you'll see a post from pikamonstruosa talking more about the trip, but for now, stay tuned with the Brazil team for IOI, OII, and EGOI!

IOI team:

1. _rey
2. Pedro Assunção
3. Pagode_Paiva
4. clarinha

OII team:

1. _rey
2. Pedro Assunção
3. Pagode_Paiva
4. clarinha
5. DereFer
6. Gustavo-d
7. pikamonstruosa
8. LucasCGar
9. ortsac
10. Cabralbonzao

EGOI team:

1. clarinha
2. estela
3. Sofiatpc
4. GabrielaBS

Congratulations for everyone!! And also a huge thanks for all setters, the Brazil test keep getting better and better. Looking forward for next year!

Hi, my name is Paiva, I'm 17 years old and I live in Brazil. Last week, we had the Brazilian Team Selection Test for IOI, and I got 6th place. I spend all this year studying for this test, and I really thought that I would go to IOI this year, but I was defeated. I should be thinking about how I lost a great opportunity for my life, right? I should feel sad, right? In fact, I could not be happier.

I started doing Olympiads in my 7th grade (2019), with mathematics Olympiads, and since then, I had a dream to go to IMO, and since then I spent almost all of my time studying for make this dream come true, but I never thought if I was enjoying what I was doing. After some time, I wasn't liking what I was doing, it fell just like an obligation, but I could not stop, because I thought that if I dropped it, I wouldn't find something worth fighting for.

It was in 2021 that I started learning about competitive programming, and I really fell in love with it. It had everything that I liked in mathematics and everything that I disliked wasn't there. I had about 2 class a week about cp, and it was always magical. But again, I didn't wanted to give up mathematics because I already spent about 2 years just studying for it, and I thought that all this time that I study would be for nothing, so I put CP as a second plan.

But everything changed in 2022. In South America, we have a math olympiad called ConoSur, and 4 people with less than 16 years old can participate, and they select this team with two tests. After the first test, I was in second place, and I was probably in the team, but, after the second test, I did very poorly, and then fell to the 8th place, losing my spot in the team. After that, I couldn't look more to mathematics, and then, I started to give more chance to cp.

After some time studying just competitive programming, I realized that this is what I wanted to do in my life, and then, in the start of 2023, I decided that I would give up mathematics, and just study informatics, and now here I am. I lost a opportunity again, so why am I happy? Because I finally found something that I love to do. When I was doing the tests for IOI, I never was distracted with thoughts like: "I will really go to IOI? Are the other people doing better than me?" and that is because I was just thinking about the problems and having fun, so, even thought I have lost the spot on the team, I won because I was having fun during the test, and that was something that I never felt with math.

So, what about now? I will keep studying informatics. I'm in the second grade of high school, so I still have one more attempt to go to IOI, and I will make my best to get that spot. So, why am I making this blog in first place? I want this to be a reminder for me. Everyday that I fell demotivated, I will open this blog, and remember why am I still studying in the first place: Because I love it. I hope to get my spot in IOI 2025, and I will make my best for make my dream come true.

And I would also like to thank some people:

• I would like to thanks the setters of the TST, you guys made a incredible test, it was really fun, and I loved all the problems
• I would like to thanks all my informatics teachers: MatheusLealV, that gave me my firsts informatics classes, and it was with him that I learned many basics algorithms. Luca and Leonardo_Paes, that gave me many classes about some harder things, and made me learn even more about cp. NaimSS and yan.silva, that give me classes until today, and helped me a lot to improve.
• And the most important, I would like to thanks my teacher and friend, LoboLobo, who helped me every time I asked and always put faith on me.

And also, congratulations for all the participants of the team of IOI and OII (Ibero-american)!

1. _rey

2. LoboLobo

3. Lalic

4. clarinha

5. Pedro Assunção

6. Pagode_Paiva

7. Cabralbonzao

8. leanchec

9. DereFer

10. Enzinho

(The top 4 is the IOI team and the top 10 is the OII team)

Heyy :)

Yesterday I was studying convex hull, and I came across with this problem. It is very cute, where you need to make a geometry interpretation, and then realize that the lower hull is the answer, but I really don't know how to came up with solutions like this, and I tried to search some problems with similar ideias, but I couldn't find. Could you send some problems with nice geometry interpretations for me?