# Cheng-Yuan Lee

![Cheng-Yuan Lee](/resources/cognition/portraits/sam-lee.webp)

ML @ Cognition | ICPC ’23/24 World Finalist  
Cognition  
San Francisco Bay Area

## At Cognition

- Role: Member of Technical Staff (Engineering)
- Joined: May 2025
- How they joined: With Windsurf (https://www.autumn.ai/resources/cognition/acquisitions/windsurf)
- Before Windsurf: CMSC452 (Elementary Theory of Computation) TA, University of Maryland

## Identity
- LinkedIn: https://www.linkedin.com/in/sam571128
- X: @cl571128
- GitHub: https://github.com/sam571128

## Notes
- Posted on X: "@ain3sh Congrats Ainesh. Let me know if you need help getting correct results from Devin CLI" (https://x.com/cl571128/status/2115977743687094434)
- Posted on X: "FrontierCode 2.0 is here!

With recent model releases, it almost feels like SWE is a solved problem. Yet anyone who uses coding agents regularly knows how frustrating it can be when models fail to think through details and deliver thorough implementations.

Still more work to do!" (https://x.com/cl571128/status/2115142467691720819)
- Posted on X: "We worked closely with Artificial Analysis to bring FrontierCode to the Coding Index. I think it’ll be a great addition that helps us better understand model capabilities!" (https://x.com/cl571128/status/2109704280005603358)
- Posted on X: "Agree with this. Really happy to see that there’s finally a third party doing independent evaluation verification. This is really important for making sure the field doesn’t get stalled by benchmark quality issues, like what happened with SWE-Bench Pro when every model was stuck around 60%.

I also really appreciate how much effort the Terminal-Bench authors have put into making sure we have a hig" (https://x.com/cl571128/status/2101105869668700292)
- Posted on X: "Since I started using Devin a lot late last year, I haven’t been able to go back. The interaction just feels natural, and.

Do it all with Devin!" (https://x.com/cl571128/status/2090157016954417194)
- Public headline says "ML @ Cognition | ICPC ’23/24 World Finalist". (https://www.linkedin.com/in/sam571128)
- Serves as student assistant coach for the University of Maryland ICPC team, with support role alongside coach Professor Mohammad Hajiaghayi. (https://www.linkedin.com/posts/department-of-computer-science-umd_a-student-team-from-the-university-of-maryland-activity-7444392777305481216-WVUN?utm_source=social_share_send&utm_medium=member_desktop_web&rcm=ACoAAHCgeYIBwuHlpJvlJFXJfm2lCclqPEMeCiw)
- Previous roles include Software Engineer Intern at Cognition; Software Engineer Intern at Windsurf; Technical Advisor Intern - GenAI at Scale AI; CMSC398L (Introduction to Competitive Programming) Instructor at University of Maryland; CMSC451 (Design and Analysis of Computer Algorithms) TA at University of Maryland; CMSC452 (Elementary Theory of Computation) TA at University of Maryland. (https://www.linkedin.com/in/sam571128)
- The UMD team he assistant-coached (Danny Mittal, Sujay Konda, Austin Zou) earned a silver medal at the 2026 ICPC North America Championship. (https://www.linkedin.com/posts/department-of-computer-science-umd_a-student-team-from-the-university-of-maryland-activity-7444392777305481216-WVUN?utm_source=social_share_send&utm_medium=member_desktop_web&rcm=ACoAAHCgeYIBwuHlpJvlJFXJfm2lCclqPEMeCiw)
- Stated that there is still a lot more to coding than what any single benchmark can measure, and that this is another step toward a more complete picture. (https://www.linkedin.com/posts/sam571128_were-launching-our-leaderboard-for-frontiercode-activity-7515478361838686208--81D?utm_source=social_share_send&utm_medium=member_desktop_web&rcm=ACoAAHCgeYIBwuHlpJvlJFXJfm2lCclqPEMeCiw)
- The UMD team he assistant-coached advances to the ICPC World Finals in Dubai in November 2026. (https://www.linkedin.com/posts/department-of-computer-science-umd_a-student-team-from-the-university-of-maryland-activity-7444392777305481216-WVUN?utm_source=social_share_send&utm_medium=member_desktop_web&rcm=ACoAAHCgeYIBwuHlpJvlJFXJfm2lCclqPEMeCiw)
- Cheng-Yuan Lee competed in ICPC 2024 World Finals on 2024-09-19 with University of Maryland team UMD WHITE, ranked 134, score 2/12. (https://cphof.org/profile/icpc:Cheng-Yuan%20Lee)
- Cheng-Yuan Lee's ICPC 2024 World Finals teammates were Colin Galen and Shayan Chashm Jahan (UMD WHITE). (https://cphof.org/profile/icpc:Cheng-Yuan%20Lee)
- Cheng-Yuan Lee's ICPC 2023 World Finals teammates were Colin Galen (UMD RED). (https://cphof.org/profile/icpc:Cheng-Yuan%20Lee)
- Competed in the 2021 Taipei Contest. (https://sam571128.codes/)
- Authored a blog post about his experience in the 資訊之芽 (Sprout) program, noting both stages ended and his Codeforces rating returned to blue after the preliminary selection. (https://sam571128.codes/)
- Scored 152/500 in a contest (TOI-related), higher than his first-year score of 130 and the 女保 score of 124, but felt his 11 months of practice as a second-year student had not paid off. (https://sam571128.codes/)
- Location is San Francisco Bay Area. (https://www.linkedin.com/in/sam571128)
- Pinned repository mdurrani808/DatacenterEmulatorProject (owned by mdurrani808) (https://github.com/sam571128)
- GitHub achievements: Pull Shark x4, Pair Extraordinaire x4, YOLO, Quickdraw. (https://github.com/sam571128)
- Cheng-Yuan Lee has a Codeforces account with handle sam571128 and a rating of 2162. (https://clist.by/coder/%E2%88%A86859470/)
- Cheng-Yuan Lee is associated with University of Maryland on ICPC (icpc.global). (https://clist.by/coder/%E2%88%A86859470/)
- Credited as a researcher in the acknowledgments section (Research list) alongside Eric Lu, Ben Pan, Deniz Birlikci, Ray Wang, Rohan Choudhury, Fermi Ma, TC Qin, Carlo Baronio, and Silas Alberti. (https://cognition.com/blog/frontier-code)
- Worked closely with the Artificial Analysis team to make FrontierCode's addition to the Coding Index happen. (https://www.linkedin.com/posts/sam571128_were-launching-our-leaderboard-for-frontiercode-activity-7515478361838686208--81D?utm_source=social_share_send&utm_medium=member_desktop_web&rcm=ACoAAHCgeYIBwuHlpJvlJFXJfm2lCclqPEMeCiw)
- Stated that FrontierCode brings a valuable new perspective to evaluating coding models and hopes it helps the community better understand what these models are capable of. (https://www.linkedin.com/posts/sam571128_were-launching-our-leaderboard-for-frontiercode-activity-7515478361838686208--81D?utm_source=social_share_send&utm_medium=member_desktop_web&rcm=ACoAAHCgeYIBwuHlpJvlJFXJfm2lCclqPEMeCiw)
- Cheng-Yuan Lee competed in Educational Codeforces Round 179 (Rated for Div. 2) on 2025-06-03. (https://clist.by/coder/%E2%88%A86859470/)
- Cheng-Yuan Lee competed in Codeforces Round 1026 (Div. 2) on 2025-05-24. (https://clist.by/coder/%E2%88%A86859470/)
- Learned about large language models (LLMs) and their architectures during his first two weeks. (https://www.linkedin.com/posts/sam571128_im-excited-to-share-that-ive-started-as-activity-7336929789791858688-y8ZZ)
- Was reached out to on LinkedIn by Peter Pitetta during the winter. (https://www.linkedin.com/posts/sam571128_im-excited-to-share-that-ive-started-as-activity-7336929789791858688-y8ZZ)
- Recruiting process was made seamless by Ruila M. (https://www.linkedin.com/posts/sam571128_im-excited-to-share-that-ive-started-as-activity-7336929789791858688-y8ZZ)
- Sam (sam571128) had a final training session the day before the AUA, ahead of ICPC WF 2024. (https://codeforces.com/blog/entry/133825)
- Authored CMSC451-F24-Programming-Problems (CMSC451 Fall 2024 programming homework problem and testcases) (https://github.com/sam571128)
- AtCoder handle SamDaBest, rated 1 Dan with rating 2044 and highest rating 2044 (73 rated matches, last competed 2023-01-29) (https://atcoder.jp/users/SamDaBest)
- Authored a blog post explaining the concept of Xor Basis (linear basis), motivated by learning about vector spaces at school. (https://sam571128.codes/)
- Authored a blog post on Slope Trick DP optimization, which he learned while solving CSES problems. (https://sam571128.codes/)
- Authored a blog post on Dirichlet convolution and Möbius inversion, motivated by Codeforces Round 1559 problem E. (https://sam571128.codes/)
- Authored a blog post on computing combinatorial sums with binomial coefficients, which he learned with guidance from 呆呆獸 and others after seeing Codeforces 932E discussed on Discord. (https://sam571128.codes/)
- Cheng-Yuan Lee has a Codeforces profile with handle sam571128. (https://cphof.org/profile/icpc:Cheng-Yuan%20Lee)
- Based in Bay Area (profile also lists United States) (https://github.com/sam571128)
- Interested in Algorithms, LLMs, ML Infra, Inference, RL. (https://github.com/sam571128)
- Codeforces Master / AtCoder 1 Dan (Rating > 2000) (https://github.com/sam571128)
- Taught competitive programming @ Wego Informatics Club. (https://github.com/sam571128)
- Authored CP-Slides repository containing slides he made. (https://github.com/sam571128)
- Authored CP-Templates (sam571128's CP templates) (https://github.com/sam571128)
- Contributed to HHSH-CYSH-WGSH-HSNU-Summer-Camp/Greedy (貪心) and HHSH-CYSH-WGSH-HSNU-Summer-Camp/Computational-Geometry (計算幾何) (https://github.com/sam571128)
- GitHub handle sam571128; LinkedIn: Cheng-Yuan Lee; email  (https://github.com/sam571128)
- Country/Region: Taiwan; birth year 2004. (https://atcoder.jp/users/SamDaBest)
- Codeforces ID sam571128. (https://atcoder.jp/users/SamDaBest)
- Affiliation: University of Maryland. (https://atcoder.jp/users/SamDaBest)
- Cheng-Yuan Lee has a cphof.org (Competitive Programming Hall of Fame) account entry. (https://clist.by/coder/%E2%88%A86859470/)
- Authored a LinkedIn post expressing excitement that FrontierCode was added to Artificial Analysis' Coding Index. (https://www.linkedin.com/posts/sam571128_were-launching-our-leaderboard-for-frontiercode-activity-7515478361838686208--81D?utm_source=social_share_send&utm_medium=member_desktop_web&rcm=ACoAAHCgeYIBwuHlpJvlJFXJfm2lCclqPEMeCiw)
- Credited as co-author (S. Lee) on 'FrontierCode 1.1' alongside E. Lu, B. Pan, F. Ma, A. Lombardi, D. Birlikci, R. Wang, R. Choudhury, T. Qin, C. Baronio, J. Teo, J.H. Lee, S. Alberti. (https://cognition.com/blog/swe-2)
- Credited as co-author (S. Lee) on 'SWE-1.7: Frontier Intelligence at a Fraction of the Cost' alongside B. Pan, C. Baronio, R. Choudhury, E. Lu, R. Kim, D. Birlikci, T. Qin, F. Ma, A. Liu, Y. Liu, S. Panda, J. Teo, R. Wang, G. Chang, S. Cao, S. Alberti. (https://cognition.com/blog/swe-2)
- Cheng-Yuan Lee competed in Codeforces Round 1064 (Div. 2) on 2025-11-16. (https://clist.by/coder/%E2%88%A86859470/)
- Cheng-Yuan Lee competed in Codeforces Round 1039 (Div. 2) on 2025-07-27. (https://clist.by/coder/%E2%88%A86859470/)
- Cheng-Yuan Lee competed in Codeforces Round 1035 (Div. 2) on 2025-07-05. (https://clist.by/coder/%E2%88%A86859470/)
- Cheng-Yuan Lee competed in Codeforces Round 1023 (Div. 2) on 2025-05-05. (https://clist.by/coder/%E2%88%A86859470/)
- Cheng-Yuan Lee competed in Educational Codeforces Round 178 (Rated for Div. 2) on 2025-04-28. (https://clist.by/coder/%E2%88%A86859470/)
- Cheng-Yuan Lee competed in Codeforces Round 1021 (Div. 2) on 2025-04-26. (https://clist.by/coder/%E2%88%A86859470/)
- Cheng-Yuan Lee competed in Codeforces Round 1021 (Div. 1) on 2025-04-26. (https://clist.by/coder/%E2%88%A86859470/)
- Cheng-Yuan Lee competed in Codeforces Round 1019 (Div. 2) on 2025-04-21. (https://clist.by/coder/%E2%88%A86859470/)
- Started as a Software Engineer Intern at Windsurf for the summer. (https://www.linkedin.com/posts/sam571128_im-excited-to-share-that-ive-started-as-activity-7336929789791858688-y8ZZ)
- Member of the Inference Server team at Windsurf. (https://www.linkedin.com/posts/sam571128_im-excited-to-share-that-ive-started-as-activity-7336929789791858688-y8ZZ)
- Works closely with his manager, Brian Shimanuki. (https://www.linkedin.com/posts/sam571128_im-excited-to-share-that-ive-started-as-activity-7336929789791858688-y8ZZ)
- Sam (handle sam571128) is a member of the UMD White ICPC team, along with Colin (galen_colin) and Shayan. (https://codeforces.com/blog/entry/133825)
- Sam (sam571128) was scheduled to participate in an AUA (Ask Us Anything) with teammates Colin (galen_colin) and Shayan ahead of ICPC WF 2024, discussing their ICPC goals and preparation. (https://codeforces.com/blog/entry/133825)
- Sam (sam571128) was heading to Kazakhstan for ICPC WF 2024, departing Friday night before the contest week. (https://codeforces.com/blog/entry/133825)
- ICPC North America Championship 2024 - South Region Champion. (https://github.com/sam571128)
- ML Infra @ Cognition (listed as current role; also 'ML/RL Infra @ Cognition') (https://github.com/sam571128)
- Previously Software Engineer Intern @ Windsurf (Acquired By Cognition) (https://github.com/sam571128)
- Previously Technical Advisor Intern @ Scale AI. (https://github.com/sam571128)
- Senior at University of Maryland, double major in Computer Science & Math. (https://github.com/sam571128)
- ICPC World Finalist 2023/2024. (https://github.com/sam571128)
- Initiated the Competitive Programming Club & became president of the club @ University of Maryland. (https://github.com/sam571128)
- Designed and taught CMSC398L - Intro to Competitive Programming @ University of Maryland. (https://github.com/sam571128)
- TA'ed for CMSC451 - Design and Analysis of Algorithms and CMSC452 - Theory of Computation @ University of Maryland. (https://github.com/sam571128)

## Experience
- Member of Technical Staff at Cognition (Sep 2025 - Present): Research:
- LLM Evaluation
- Data Pipeline
- RL Framework
- Inference
With main focus on RL data and evaluations
- Software Engineer Intern at Cognition (Jul 2025 - Aug 2025): On-policy RL infrastructure + Inference
- Software Engineer Intern at Windsurf (May 2025 - Aug 2025): (acquired by Cognition)

Inference Infrastructure
- Technical Advisor Intern - GenAI at Scale AI (Nov 2024 - May 2025): Frontier Coding/Math/STEM, RL environments for SWE, Humanity's Last Exam
- CMSC398L (Introduction to Competitive Programming) Instructor at University of Maryland (Sep 2023 - May 2025): Fall '23, '24 / Spring '24, '25

Initiated the course & designed the syllabus.
- CMSC451 (Design and Analysis of Computer Algorithms) TA at University of Maryland - College Park, Maryland, United States (Aug 2023 - Dec 2024): Fall '23/'24
- CMSC452 (Elementary Theory of Computation) TA at University of Maryland - College Park, Maryland, United States (Jan 2024 - May 2024): Spring '24

## Education
- University of Maryland - Bachelor of Science - BS, Mathematics and Computer Science - (Aug 2022 - Dec 2025): - Double Major in CS & Math
- Two time ICPC World Finalist
- ICPC Co-coach
- President @ Competitive Programming Club
- Algorithm Researcher
- HSPC Problemsetter

## Sources
- https://www.linkedin.com/in/sam571128
- https://x.com/cl571128
- https://cognition.com/blog/frontier-code
- https://atcoder.jp/users/SamDaBest
- https://clist.by/coder/%E2%88%A86859470/
- https://sam571128.codes/
- https://cphof.org/profile/icpc:Cheng-Yuan%20Lee
- https://cognition.com/blog/swe-2
- https://github.com/sam571128
- https://www.linkedin.com/in/sam571128?miniProfileUrn=urn%3Ali%3Afsd_profile%3AACoAADSYzdABt3bHGLlo7f41QTr7U8Iw7WNq9GY
- https://www.linkedin.com/posts/sam571128_im-excited-to-share-that-ive-started-as-activity-7336929789791858688-y8ZZ
- https://codeforces.com/blog/entry/133825
- https://www.linkedin.com/company/department-of-computer-science-umd/posts
- https://x.com/cl571128/status/2115977743687094434
- https://x.com/cl571128/status/2115142467691720819
- https://x.com/cl571128/status/2109704280005603358
- https://x.com/cl571128/status/2101105869668700292
- https://x.com/cl571128/status/2090157016954417194
- https://www.linkedin.com/posts/department-of-computer-science-umd_a-student-team-from-the-university-of-maryland-activity-7444392777305481216-WVUN?utm_source=social_share_send&utm_medium=member_desktop_web&rcm=ACoAAHCgeYIBwuHlpJvlJFXJfm2lCclqPEMeCiw
- https://www.linkedin.com/posts/sam571128_were-launching-our-leaderboard-for-frontiercode-activity-7515478361838686208--81D?utm_source=social_share_send&utm_medium=member_desktop_web&rcm=ACoAAHCgeYIBwuHlpJvlJFXJfm2lCclqPEMeCiw


Researched with Autumn (https://www.autumn.ai) from public sources. Updated 2026-11-04. Profile: https://www.autumn.ai/resources/cognition/people/sam-lee · Everyone at Cognition: https://www.autumn.ai/resources/cognition/people