Brodal queue

In computer science, the Brodal queue is a heap/priority queue structure with very low worst case time bounds: $O(1)$ for insertion, find-minimum, meld (merge two queues) and decrease-key and $O(\mathrm{log}(n))$ for delete-minimum and general deletion; they are the first heap variant with these bounds. Brodal queues are named after their inventor Gerth Stølting Brodal.^[1]

While having better asymptotic bounds than other priority queue structures, they are, in the words of Brodal himself, "quite complicated" and "[not] applicable in practice."^[1] Brodal and Okasaki describe a persistent (functional) version of Brodal queues.^[2]

References

1. Gerth Stølting Brodal (1996). Worst-case efficient priority queues. Proc. 7th ACM-SIAM Symposium on Discrete Algorithms, pp. 52–58
2. Gerth Stølting Brodal and Chris Okasaki (1996). Optimal purely functional priority queues. J. Functional Programming.