Priority queues and multisets

M. D. Atkinson ; S. A. Linton ; L. A. Walker

The electronic journal of combinatorics, Tome 2 (1995)

Résumé

A priority queue, a container data structure equipped with the operations insert and delete-minimum, can re-order its input in various ways, depending both on the input and on the sequence of operations used. If a given input $\sigma$ can produce a particular output $\tau$ then $(\sigma,\tau)$ is said to be an allowable pair. It is shown that allowable pairs on a fixed multiset are in one-to-one correspondence with certain k-way trees and, consequently, the allowable pairs can be enumerated. Algorithms are presented for determining the number of allowable pairs with a fixed input component, or with a fixed output component. Finally, generating functions are used to study the maximum number of output components with a fixed input component, and a symmetry result is derived.

Détail

DOI : 10.37236/1218

Classification : 90B22
Mots-clés : priority queue, allowable pairs on a fixed multiset