Linear-time algorithm for the tree case

Determine whether the restricted inverse optimal value problem on shortest paths under the weighted l∞ norm on trees admits an O(n)-time algorithm, improving on the two O(n log n)-time algorithms developed in the paper.

Background

The paper presents two exact algorithms for the tree-based restricted inverse optimal value problem, and both have O(n log n) running time. The authors explicitly leave unresolved whether the problem can be solved in linear time.

References

Second, both of our algorithms run in O(n log n) time. Whether a linear-time algorithm exists remains open.

— The Restricted Inverse Optimal Value Problem on Shortest Path under $l_\infty$ Norm on Trees  (2610.23710 - Zhang et al., 16 Oct 2026) in Conclusion, p. 35