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Changyeol Lee

Ph.D student in Computer Science and Engineering, Yonsei University
Advisor: Prof. Hyung-Chan An
Email - 777john_at_yonsei_dot_ac_dot_kr

Hello! I am a Ph.D. student in the Combinatorial Optimization Lab at the Department of Computer Science and Engineering, College of Computing, Yonsei University, in Seoul, South Korea, advised by Prof. Hyung-Chan An. I expect to graduate in February 2027. I received my B.S. in Computer Science and Engineering from Yonsei University in February 2021.

My main research interests are approximation algorithms, online algorithms, and learning-augmented algorithms. More broadly, I am interested in theoretical computer science and combinatorial optimization, and I enjoy learning about a wide range of topics. I am always open to collaboration and happy to chat about research ideas!

I am a co-organizer of the Yonsei CS Theory Student Group, where I help run reading groups on various topics in theoretical computer science. I also co-organized the Workshop on Algorithm for Students (WAS) in 2025 and 2026.

I am currently doing research while fulfilling my mandatory military service in South Korea under the Expert Research Personnel (전문연구요원) program. My service is expected to end in February 2028.

RESEARCH INTERESTS

  • Approximation Algorithm
  • Online Algortihm
  • Learning-augmented Algorithm
  • Combinatorial Optimization
  • Miscellaneous (Theoretical Computer Science, Game Theory and Mechanism Design, Quantum algorithms)

EDUCATION

  • Ph.D. in Computer Science and Engineering, Yonsei University (2021.02-2027.02, expected)
  • B.S. in Computer Science and Engineering, Yonsei University (2017.03-2021.02)

TEACHING EXPERIENCE

  • Teaching Assistant @ Yonsei Univ.
    • Algorithm Analysis CSI3108 (Fall 2021, Fall 2023)
    • Data Structures CSI2103 (Spring 2021), CCO2103 (Spring 2023)
  • Tutor @ Yonsei Univ.
    • Algorithm Analysis CSI3108 (Fall 2019, Fall 2020)
    • Linear Algebra MAT2011 (Spring 2019)
  • Peer Mentor (Head Mentor) of Yonsei-Nexon RC Creative Platform (2018-2020)

AWARDS

  • High Honors At (B.S.) Graduation @ Yonsei University (2021.02)
  • RC Creative Platform Grand Prize, Yonsei University & NEXON Co., Ltd. (2017.11)

SELECTED PUBLICATIONS

[All Publications]
  • Ultrametric Violation Distance with Upper and Lower Bounds: A 4-Approximation (To appear in ISAAC 2026)
    joint work with Hyung-Chan An