A Framework for Speeding Up Priority-Queue Operations

We introduce a framework for reducing the number of element compari- sons performed in priority-queue operations. In particular, we give a priority queue which guarantees the worst-case cost of O(1) per minimum finding and insertion, and the worst-case cost of O(logn) with at most logn+O(1) element comparisons per minimum deletion and deletion, improving the bound of 2logn + O(1) on the number of element comparisons known for binomial queues. Here, n denotes the number of elements stored in the data structure prior to the operation in question, and logn equals max{1,log 2 n}. We also give a priority queue that provides, in addition to the above-mentioned methods, the priority-decrease (or decrease-key) method. This priority queue achieves the worst-case cost of O(1) per minimum finding, insertion, and priority decrease; and the worst-case cost of O(logn) with at most logn+O(loglogn) element comparisons per minimum deletion and deletion. CR Classification. E.1 (Data Structures): Lists, stacks, and queues; E.2 (Data Storage Representations): Linked representations; F.2.2 (Analysis of Algorithms and Problem Complexity): sorting and searching