PACE 2027

Problem

This year features the $k$-Path problem of finding a path of length $k$ in a graph. For definitions, format specification, and literature, see Problem Specification. See also the IPEC’26 Announcement Slides.

Timeline

• September 2026: Announcement of the challenge and tracks ✅
• October 2026: Definition of input and output formats, tiny test set, and verifier ✅
• January 2027: Release of public instances and details about the benchmark
• April 2027: Submission via optil.io opens
• Early July 2027: Final submission deadline
• Mid-July 2027: Solver review phase
• End of July 2027: Announcement of results

Tracks

The challenge features three distinct tracks:

1. an “exact unweighted” track – output the largest integer $k$ in an undirected unweighted graph $G$ such that $G$ contains a $k$-path together with the path as a witness.
2. an “exact weighted” track – output a $k$-path of maximum weight for a given $k$ in a weighted directed graph.
3. a “heuristic” track – output a valid lower bound for the maximum path length in an undirected unweighted graph, computed within a reasonable time limit, and a path witnessing the lower bound.

Zulip

Join us on Zulip for discussions and updates.

Program Committee

• Juha Harviainen (University of Helsinki, Finland)
• André Schidler (University of Freiburg, Germany)
• Frank Sommer (University of Jena, Germany)