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Changyeol Lee

Graduate student studying Computer Science at Yonsei Univ.
Combinatorial Optimization Lab (Advisor - Prof. Hyung-Chan An)
Email - 777john_at_yonsei.ac.kr or changyeollee_at_yonsei.ac.kr

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 student at Yonsei Univserity (advised by Prof. Hyung-Chan An)
  • B.S. in Computer Science, Yonsei Univ. (2017.03-2021.02)

TEACHING EXPERIENCE

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

AWARDS

  • High honors at (B.S.) graduation @ Yonsei Univ. (2021.02)
  • RC Creative Platform Grand Prize, Yonsei Univ. & NEXON Co., Ltd. (2017.11)

RESEARCH EXPERIENCE

  • 2026.6.10 – 2026.6.11

    Visited DGIST, South Korea, invited by Dr. Eunku Park
    Gave a talk at DGIST Theoretical Computer Science Seminar on Handling LP-Rounding for Hierarchical Clustering and Fitting Distances by Ultrametrics

  • 2026.4.21 – 2026.4.23

    Invited speaker at NYCU Theory Day
    Talk on Handling LP-Rounding for Hierarchical Clustering and Fitting Distances by Ultrametrics

  • 2025.1.2 – 2025.1.4

    Co-organized WAS 2026
    (with Hyeonjun Shin)

  • 2025.12.13 – 2025.12.18

    Gave a talk at FOCS 2025, Session 10A

  • 2025.12.2 – 2025.12.7

    Presented a poster at NeurIPS 2025

  • 2025.6.15 – 2025.6.21

    Visited University of Wrocław, Poland, invited by Prof. Jarosław Byrka
    Gave a talk at C⚙G seminar on Handling LP-Rounding for Hierarchical Clustering and Fitting Distances by Ultrametrics

  • 2025.1.2 – 2025.1.4

    Co-organized WAS 2025
    (with Shinwoo An, Kyungjin Cho, Juwon Kim)

  • 2024.10.23 – 2024.10.26

    Visited National Yang-Ming Chiao-Tung University (NYCU), Taiwan, invited by Prof. Mong-Jen Kao

  • 2024.8.2 – 2024.8.3

    Speaker at WAAC 2024, Session 10
    Talk on learning-augmented algorithms for multi-option ski-rental

  • 2024.03. – current

    Co-organizer of Yonsei CS Theory Student Group
    (with Sungmin Kim)

  • 2023.10.27 – 2023.10.28

    Speaker at FWAC 2023, Session 3
    Talk on learning-augmented algorithms for multi-option ski-rental

  • 2023.10.27 – 2023.10.28

    Presented a poster at ICML 2023

  • 2022.09. – 2022.10.

    Visiting Research Intern, Cornell University, advised by Prof. David Shmoys

  • 2018.12. – 2021.02.

    Research Intern, Yonsei University, advised by Prof. Hyung-Chan An

RECENT PUBLICATIONS

[All Publications]
  1. Ultrametric Violation Distance with Upper and Lower Bounds: A 4-Approximation
    Lee, Changyeol, and An, Hyung-Chan
    In 37th International Symposium on Algorithms and Computation (ISAAC, to appear), Dec, 2026
  2. Approximating (Weighted) Chromatic Correlation Clustering via Cluster LP
    Abbasi, Fateme, An, Hyung-Chan, Byrka, Jarosław,  Lee, Changyeol, and Shin, Yongho
    In 29th International Conference on Approximation Algorithms for Combinatorial Optimization Problems (APPROX), Aug, 2026
  3. Optimal Learning-Augmented Algorithm for Online Bidding
    Lee, Changyeol, Lee, Dahoon, Lee, Jongseo, Shin, Yongho, and Yun, Changki
    arXiv preprint arXiv:2605.07349, May, 2026
  4. Handling LP-Rounding for Hierarchical Clustering and Fitting Distances by Ultrametrics
    An, Hyung-Chan, Kao, Mong-Jen,  Lee, Changyeol, and Lee, Mu-Ting
    In IEEE 66th Annual Symposium on Foundations of Computer Science (FOCS), pp. 1144-1169, Dec, 2025
  5. Improved Algorithms for Overlapping and Robust Clustering of Edge-Colored Hypergraphs: An LP-Based Combinatorial Approach
    Lee, Changyeol, Shin, Yongho, and An, Hyung-Chan
    In The Thirty-ninth Annual Conference on Neural Information Processing Systems (NeurIPS), vol. 38, pp. 78913–78945, Dec, 2025
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