A C99 implementation of the DMMSY algorithm, presented in STOC 2025, achieves unprecedented speedups for single-source shortest path problems. The implementation by Ran Duan and colleagues breaks the long-standing $O(m + n log n)$ complexity barrier, delivering performance improvements exceeding 20,000x over standard Dijkstra implementations.

Built with a recursive subproblem decomposition approach rather than traditional priority queues, the algorithm reduces complexity to $O(m log^{2/3} n)$. The codebase features a zero-allocation design with pre-allocated workspaces, cache-optimized Compressed Sparse Row storage, and modular architecture separating utilities from core implementations. Tests on x86_64 architecture with Clang -O3 and LTO optimizations show maximum performance gains on graphs with 250k-1M+ nodes.

This implementation represents a significant advance in graph algorithm efficiency, particularly for large-scale sparse networks. The project's clean separation between baseline Dijkstra and optimized DMMSY implementations enables straightforward performance comparisons. With dual licensing under MIT and Apache 2.0, the codebase provides both academic and practical value for developers working on high-performance graph processing applications.