DUdunmalg·Feb 23, 2026Submission
Issues with "C99 implementation of new O(m log^(2/3) n) shortest path algorithm"
2 points · Open discussiondanalec
DMMSY-SSSP
C2026–2026
danalec / DMMSY-SSSP
DMMSY-SSSP
Experimental C implementation of “Breaking the Sorting Barrier for Directed Single-Source Shortest Paths” by Ran Duan, Jiayi Mao, Xiao Mao, Xinkai Shu, and Longhui Yin (STOC 2025)
2Distinct people
3Mentions
0Explicit recommenders
89GitHub stars
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What it is
Experimental C implementation of “Breaking the Sorting Barrier for Directed Single-Source Shortest Paths” by Ran Duan, Jiayi Mao, Xiao Mao, Xinkai Shu, and Longhui Yin (STOC 2025)
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This week on Hacker News
Nov 7–Nov 14 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/14/2026, 3:56:07 PM UTC.
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Mentions over time
HN mentions by hour3 dated mentions
Observed mentions: 2026-02-23 16:14:10 UTC to 2026-02-23 18:44:00 UTC.
Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.
View mention counts and date ranges
| Period | Start (UTC) | End (exclusive, UTC) | Mentions | Submissions | Comments |
|---|---|---|---|---|---|
| Feb 23, 16:00 | 2026-02-23 16:00:00 UTC | 2026-02-23 17:00:00 UTC | 2 | 1 | 1 |
| Feb 23, 17:00 | 2026-02-23 17:00:00 UTC | 2026-02-23 18:00:00 UTC | 0 | 0 | 0 |
| Feb 23, 18:00 | 2026-02-23 18:00:00 UTC | 2026-02-23 19:00:00 UTC | 1 | 1 | 0 |
What Hacker News says
3 sourcesShow HN: C99 implementation of new O(m log^(2/3) n) shortest path algorithm
111 points · Open discussionI implemented the STOC 2025 Best Paper Award winner in C99. The algorithm achieves O(m log^(2/3) n) complexity, breaking the 65-year-old sorting barrier for sparse directed SSSP that Dijkstra established at O(m + n log n).
*Key implementation details:*
- Cache-optimized CSR layout for maximum spatial locality
- Zero-allocation design with pre-allocated workspaces
- Recursive subproblem decomposition instead of global priority queues
*Benchmarks:* On graphs with 250k–1M nodes, this shows 20,000x+ speedups over standard Dijkstra implementations. The DMMSY core runs in ~800ns for 1M nodes.
*Paper:* https://arxiv.org/pdf/2504.17033
*GitHub:* https://github.com/danalec/DMMSY-SSSP
This is experimental—focused on correctness first. Would love feedback on edge cases, better decomposition strategies, or cache-oblivious optimizations I might have
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