,
John Iacono
,
Eva Rotenberg
,
Daniel Rutschmann
Creative Commons Attribution 4.0 International license
A heap is a dynamic data structure that stores a set of labeled values under the following operations: pop returns the minimum value of the heap, Push(x_i) pushes a new value x_i onto the heap, and DecreaseKey(i, v) decreases the value x_i to v. A working-set heap is a heap that supports the x_i ← pop() operation in O(log Γ(x_i)) time where Γ(x_i) is the size of the working set: the number of elements that were pushed onto the heap while x_i was in the heap. The goal of working set heap design is to maintain the working set property while minimizing the overhead of the Push and DecreaseKey operations. On a word RAM, there exist working set heaps that support Push and DecreaseKey in amortized constant time. In this paper, we show via a simple construction that pointer machines, one of the most general and least-assuming computational models, support working set heaps that support Push in amortized constant time and DecreaseKey in inverse-Ackermann time. A by-product of this analysis is that Dijkstra’s shortest path algorithm can be near-universally optimal on a pointer machine - incurring only an additive O(m α(m)) overhead compared to the optimal running time for distance ordering, where m denotes the number of edges in the graph.
@InProceedings{vanderhoog_et_al:LIPIcs.ESA.2026.45,
author = {van der Hoog, Ivor and Iacono, John and Rotenberg, Eva and Rutschmann, Daniel},
title = {{Near-Optimal Working-Set Heaps and Dijkstra on Pointer Machines}},
booktitle = {34th Annual European Symposium on Algorithms (ESA 2026)},
pages = {45:1--45:13},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-445-1},
ISSN = {1868-8969},
year = {2026},
volume = {388},
editor = {Bille, Philip and Pettie, Seth and Storandt, Sabine},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ESA.2026.45},
URN = {urn:nbn:de:0030-drops-271814},
doi = {10.4230/LIPIcs.ESA.2026.45},
annote = {Keywords: Data structures, graph algorithms, amortized analysis}
}