Annyeong1

• Jeeho Yoon aka gs22059
• @ Yonsei Univ. Dept. of Computer Science
  • Graduated Gyeonggi Science HS
• Go back to Korean page here
• Sadly, my blog is exclusively in Korean for now.
• Last updated on 5th Sep 2026

Programming

I do problem solving and competitive programming. I compete in various programming competitions and sometimes organize or test them.
My max ratings are Codeforces GM and AtCoder 1 Dan. I also solved 1800+ Problems on BOJ before its shutdown and am ranked Ruby V on solved.ac.
I am contributing to the Korean competitive programming community by participating as external testers for various contests. I wrote these problemsand tested these.

Contest Writing and Management

• SUAPC 2026 Summer Practice Session (2026. 8. 24) & Main Contest (2026. 8. 25) General Director; Dify Hackathon (2026. 8. 25) Problemsetter
  • Writer of 3 problems
  • Main Contest problem selection, coordination, management, and DOMJudge administration
• SUAPC 2026 Winter & Open Contest (2026. 2. 20), Practice Session (2026. 2. 19) Problemsetter / Tester / Staff
  • Writer of 1 problem
  • Onsite contest management, etc.
• IamCoder 2024 Year-End Contest (2024. 12. 26) & Open Contest (2025. 1. 4) General Director
  • Writer of 4 problems, setter of 2 more
  • Testing, Management
• IamCoder 2024 Mid-Year Contest (2024. 8. 22) & Open Contest (2024. 8. 24) General Director
  • Writer of 3 problems, setter of 1 more
  • Testing, Management
• 2024 IamCoder Qualification Test (2024. 3. 18) & Open Contest (2024. 4. 6) Problemsetting / Testing / Management
  • Setter of all subtasks
  • Testing, Management, CMS Administration, etc.
• 2023 IamCoder Qualification Test (2023. 3. 15) & Open Contest (2023. 4. 7) Problemsetter / Problemsetting / Testing / Management
  • Writer of 1 problem, setter of 1 more

Contest Testing

• IamCoder 2026 Mid-Year Contest (2026. 8. 26) & Open Contest (2026. 8. 29)
• POSTECH Programming Contest 2026 & Open Contest (2026. 5. 16)
• 2026 IamCoder Qualification Test & Open Contest (2026. 3. 17)
• IamCoder 2025 Year-End Contest (2025. 12. 28) & Open Contest (2026. 1. 3)
• 1st GSHS x SASA Programming Contest (2025. 12. 22) & Open Contest (2026. 1. 2)
• Wise Mypol Life (2025. 12. 17) & Open Contest (2025. 12. 21)
• Lemon Cup (2025. 9. 7)
• IamCoder 2025 Mid-Year Contest Div. 1 & Div. 2 (2025. 8. 20) & Open Contest (2025. 8. 21)
• 2025 Goricon & Open Contest (2025. 6. 28)
• 2025 IamCoder Qualification Test (2025. 3. 18) & Open Contest (2025. 3. 29)
• 2025 KSA Winter Contest (2025. 2. 15)
• 2024 Kookmin Univ & Chung-Ang Univ Joint Programming Contest & Open Contest (2024. 11. 30), Practice Session & Open Contest (2024. 11. 29)
• 2nd DGUPC (2024. 10. 27) & Open Contest (2024. 11. 2)
• 2024 HEPC (2024. 5. 14) & Open Contest (2024. 5. 20)
• 2024 KSA Automata Winter Contest / Arena #22 (2024. 2. 24)
• 3rd Boramae Cup Final (2024. 2. 10) & Open Contest (Arena #20) (2024. 2. 17)
• 3rd Boramae Cup Preliminary (2024. 1. 19 ~ 21) & Open Contest (2024. 1. 21)

Contests

Research

I research other things as well as computer science things. Although, CS studies are my main interests.

• (2024. 04. ~ 11.) Efficient Solutions for k-PDMI scheduling problem on interval graphs using DLAS
  • Conducted as Creative R&E Program of KOFAC
• (2024. 01. ~ 05.) An Efficient Solution for the Interval Scheduling Maximization Problem with Interval Addition Queries
  • Submitted to Korea Institute of information and Communication Engineering, Academic Conference of Spring 2024
    • Distinction (for HS division)
• (2023. 09. ~ 2024. 05.) Algorithms for Disjoint Matching of Intervals and Disjoint k-Dimensional Matching of Proper Intervals
  • Conducted for the graduation paper of GSHS
• (2023. 03. ~ 11.) A study on supercooling mechanism of aniline aromatic compounds and their mixtures (아닐린계 방향족 화합물의 치환기 위치에 따른 과냉각의 정도에 대한 연구)
  • Silver Award, Samsung Humantech Paper Awards 30th Competition Chemistry Division for HS (2023. 11. ~ 2024. 1.)
  • Conducted as Advanced R&E Program of GSHS
• (2022. 03. ~ 11.) A Study on Algorithms for Calculating Maximum Disjoint Matching of Interval Graphs
  • Submitted to Korea Institute of information and Communication Engineering, Academic Conference of Spring 2023
    • Distinction (for HS division)
  • Conducted as Basic R&E Program of GSHS

Studies & Experiences

These are some other weird things I do/did.

Contests

• Awarded Silver Medal (Non-Math Major Division) at the 43rd College Mathematics Competition (2025. 11. 1)
• Awarded Honorable Mention at the 2022/23 Korean Linguistics Olympiad (2023. 1. 8)
• Awarded Bronze Medal at the 2020 Korean Mathematical Olympiad 2nd Round (2020. 11. 21)

Various Program Participations and Completions

• Attended 2026 IBS DIMAG Summer School on Combinatorics and Algorithms (2026. 8. 10. ~ 14.)
• Attended 2025 IBS DIMAG Summer School on Combinatorics and Algorithms (2025. 7. 14. ~ 18.)
• Attended 2024/25 CALOP Winter Lecture (2025. 1. 13. ~ 17.)
• Attended 2024 IBS DIMAG Summer School on Combinatorics and Algorithms (2024. 7. 22. ~ 26.)
• Completed KAIST Creative Global Leader Camp Winter Program 2024 (2024. 1. 22. ~ 25.)
• Completed Michigan Math & Science Scholarship Introduction to Graph Theory (2023. 07. 23. ~ 08. 03.)
• Completed Lab Equipment Field Research at SKKU Cooperative Center for Research Facilities (2023. 02. 07. ~ 09.)
• Completed 2022/23 Korean Linguistics Olympiad Winter School (2023. 1. ~ 2.)
• Completed Middle School 1st/2nd Year Course at Goyang Gifted Education Center attached to Goyang Education Support Office (2019. ~ 2020.)

Various Program Managements and Teachings

• Beginner Class Coach, 2026 Korea Summer School for the International Olympiad in Informatics (2026. 7. ~ 8.)
• Director, ICPC Sinchon 2026S (2026. 4. ~ 9.)
• Intermediate Class Mentor, ICPC Sinchon 2026W Algorithm Camp (2026. 1. ~ 2.)
• Staff, ICPC Sinchon 2026W (2025. 10. ~ 2026. 3.)
• Teaching Assistant, YCS1002 (SW Programming), University College, Yonsei University (2025-2, 2025. 9. ~ 12.)

Translations

I do English and Korean text translations, mainly from English to Korean.

• Antimatter Dimensions: 2020. 08. ~
  • I translated 21K+ words in Antimatter Dimensions, an incremental game by Hevipelle.
  • I currently am a playtester for the mobile version of the game.
• IOISTUDY: 2023. 03. ~ 12.
  • IOISTUDY is a group of students for translations of foreign programming problems. I translated problems from JOISC Season 2021/22 and wrote solutions.
• SD Maid 2: 2023. 03. ~
  • I translated 2K+ words in SD Maid 2/SE, an android app by darken.

Links

• You can contact me @ me@annyeong.one.
• If you need a faster response, or use Discord, my Discord username is Annyeong1.
• I don’t spend much time on Facebook (Jeeho Yoon), X (Annyeong1main), or Instagram (annyeong.one).
• Here is a link to my GitHub(Annyeong-One) account.
• Here are my Codeforces, Atcoder, boj.kr, solved.ac and KOISTUDY accounts.
  • You can view all of my CP profiles on clist.by.