Algorithms
The Compass
Codeforces Master · max rating 2194 →Finding the way through a hard problem — graphs, dynamic programming, number theory — and staying calm while the contest clock runs.
A quiet record of a long journey
Arvin
Algorithm Engineer · Software Engineer · Computer Scientist
ICPC World Finalist · Codeforces Master
ICPC World Finalist, now an R&D engineer in Hong Kong. A quiet traveler who collects algorithms, systems, and useful tools along the road.
Chapter I · About
The Traveler
Hello, I'm Arvin — an algorithm engineer from Indonesia. Today I'm an R&D engineer at Huawei's Hong Kong Research Center, where I work on getting the most performance out of chips.
It started in high school, with the informatics olympiad and Minecraft plugins written in Java. I fell for the puzzle of it, and I still love the small, quiet joy of seeing a solution come back Accepted. Since then the road has wandered through mobile apps, backend systems and a Computer Science degree at Universitas Indonesia, up to the ICPC World Finals in 2024, the milestone that led me to algorithm work at Huawei.
When I build something, I care about two things: that it's correct, and that it's fast. In contests I was usually the one my teammates handed the heavy-implementation problems to, and the one who planned our trips.
My colleagues describe me as kind. I'm quiet, I listen more than I talk, and I care about how the things I build feel to the people who use them. Maybe that's why I enjoy teaching, and writing problems for others to solve.
Away from the keyboard, I'm usually somewhere inside a long story: a good anime, or an open world like The Witcher 3 or Red Dead Redemption 2.
Chapter II · Skills
The Traveler's Pack
Everything I carry on the road. Hover over an item, or tap it, to see it at work.
Optimization
The Hourglass
Fotoyu: search from 4s to 0.3s →Making slow things fast without making them fragile — better queries, indexes and schema design, like taking an app's search from 4 seconds to 0.3. Lately: chip performance.
Implementation
The Clockwork
ICPC World Finals →Long, intricate problems where every gear has to mesh: heavy implementation, careful edge cases, and debugging until it's Accepted. In contests, these were the problems my teammates handed to me.
Research
The Wax Seal
My thesis →Learning an unfamiliar field from scratch and building something new in it. I began my thesis with no blockchain background; six months later I had designed a Merkle tree that gives the most-checked records the shortest proofs.
Building
Hammer & Anvil
A grader for 300+ students →Turning ideas into running systems with Go, Spring Boot, Express, Django, React, Next.js and Flutter, on PostgreSQL and MySQL — with access control and personal-data protection built in.
Teaching
The Lantern
Codeforces Round 977 →Lighting the way for others — leading the teaching-assistant team of a university algorithms course and setting its homework problems, writing problems for COMPFEST's contest (later a Codeforces round), and running Flutter study sessions at RISTEK, the faculty's student tech organization.
Chapter III · Competitions
The Trials
Competitive programming was my long training ground. ICPC is the oldest and largest programming contest for university students: teams of three, one computer, five hours.
2024 · Astana, Kazakhstan
ICPC World Finalist
World Finals 2024 · Honorable Mention
The World Finals bring together the top university teams in the world, chosen from tens of thousands of students who compete in regional contests each year. My road there ran through Jakarta, Hue City and the Asia-Pacific Championship.
2024 · On the other side of the table
Problem Setter
COMPFEST 16 Final, also run as Codeforces Round 977
I wrote the two hardest problems in the set. One was entirely mine: “Boss, Thirsty”. The title comes from Bos Haus (“Boss, thirsty?”), the call of the drink seller in our campus canteen, which our small problem-setting committee could never stop imitating. The other, “Digital Village” (easy, hard and extreme versions), began as a friend's idea that I reworked and solved myself.
-
2024
ICPC Asia-Pacific Championship
Silver Medal
-
2024
GEMASTIK Programming
Champion · Indonesia's Ministry of Education
-
2024
FINDIT Programming
Champion · Universitas Gadjah Mada
-
2023
ICPC Asia Jakarta Regional
Gold Medal
-
2023
ICPC Asia Hue City Regional
Silver Medal
-
2023
Indonesian National Contest (INC)
Champion
-
2022
Asia-Pacific Informatics Olympiad
Bronze Medal · APIO
Chapter IV · Experience
The Journey
The towns I've passed through so far, from a small village in 2017 to a city across the sea.
-
2017 — 2018
The Village of Beginnings
Independent · Minecraft Plugin Developer (Java)
Where it began: Minecraft server plugins, downloaded 70,000+ times worldwide. My first lessons in performance: keeping busy game servers running smoothly.
-
2020 — 2021
The Market Town
KelolaPro · Flutter Developer
Built a property-management mobile app in Flutter — state management, Firebase, REST APIs, and a lot of careful polishing.
-
2022 — 2026
The Academy
Universitas Indonesia · B.Sc. Computer Science · GPA 3.87
Led the mobile development team at RISTEK, the faculty's student tech organization. Was a teaching assistant for Data Structures & Algorithms, then led the TA team for Algorithm Design & Analysis and wrote its homework problem sets. Also ran the programming contest at COMPFEST 16, the university's annual IT festival.
-
2023
A First Errand
GDP Labs · Software Engineer Intern
Refactored TypeScript backend services, tuned MySQL queries and indexes, and patched security issues across the stack.
-
Early 2025
The Academy Workshop
Faculty of Computer Science, Universitas Indonesia · Software Engineer (Contract)
Added automatic grading for automata exercises to the faculty's online judge, built on JFLAP's engine, then deployed it with Docker and Ansible for 300+ students.
-
2025 — 2026
The Guild of Fotoyu
Fotoyu · Backend Engineer (intern → full-time)
Fotoyu is an Indonesian AI startup: photographers sell their photos in the app, and people find photos of themselves with a face scan. There I cut full-text search from 4s to under 0.3s, saved ~$1,600 a month by reworking the identity-verification (KYC) data layer, and kept personal data out of admin views.
-
2026 — Now
Across the Sea
Huawei Hong Kong Research Center · R&D Engineer (Algorithms)
A new city and a new kind of problem: maximizing chip performance. I'm enjoying learning its rhythm — the pace, the people, the traces of British history. Still walking.
The road continues…
Chapter V · Projects
Relics
Things I've made and carried with me.
Relic I · Research
Traffic-Aware Merkle Tree
Blockchain land registries serve two users who pull in opposite directions: traders verify single busy properties, auditors verify whole regions at once. My design groups properties by province, then builds a traffic-aware Huffman tree inside each one. On 100,000 simulated Indonesian properties it stayed within 0.3% of a pure Huffman tree on everyday transactions while cutting audit costs by 3.7–5.0%, verified on Ethereum by a custom stack-based verifier.
Bachelor's thesis · Universitas Indonesia
Relic II · 2017 — 2018
Minecraft Plugins
Java plugins for Minecraft servers, downloaded 70,000+ times around the world. Lean event handling and the right data structures kept busy servers at the full 20 ticks per second the game runs on.
Browse the plugins →Relic III · JFLAP × Judgels
Instant Grading for Automata
Ported the engine of JFLAP, a classic automata simulator, into Judgels, the faculty's online judge, so automata exercises are graded automatically. Also added contest bundles and permission-based user groups, then deployed it for 300+ students.
Integrated into the course curriculum
Chapter VI · Writing
Travel Journal
Notes written by lamplight, mostly about algorithms.
-
Planned
Bos Haus: the story behind “Boss, Thirsty”
How a drink seller's call in our campus canteen became a Codeforces problem, and what it takes to write one that strangers around the world will try to break.
-
Planned
After the World Finals: a blue lake near Almaty
The contest was the reason for the trip. What stayed with me was afterwards: a lake bluer than any photo, and quiet walks through the city at night.
-
Planned
From four seconds to three hundred milliseconds
A quiet story about a slow full-text search, and what fixing it taught me about databases.
-
Planned
A Merkle tree that knows where you live
My thesis, explained without the heavy math: shorter proofs for the records people check most.
Not written yet — these are entries I'd like to write.
Chapter VI · Contact
Send a Letter
I'm slow to start conversations, but I'm always glad when someone else does.
If you have a role in algorithms or systems in mind, or just want to talk shop — algorithms, competitive programming, or a good fantasy story — write to me. I reply slowly, but I always reply.
Also on LinkedIn and Codeforces