A Parallel Priority Queue with Constant Time Operations

We present a parallel priority queue that supports the following operations in constant time: parallel insertion of a sequence of elements ordered according to key, parallel decrease key for a sequence of elements ordered according to key, deletion of the minimum key element, and deletion of an arbitrary element. Our data structure is the first to support multi-insertion and multi-decrease key in constant time. The priority queue can be implemented on the EREW PRAM and can perform any sequence of n operations in O(n) time and O(m log n) work, m being the total number of keyes inserted and/or updated. A main application is a parallel implementation of Dijkstra’s algorithm for the single-source shortest path problem, which runs in O(n) time and O(m log n) work on a CREW PRAM on graphs with n vertices and m edges. This is a logarithmic factor improvement in the running time compared with previous approaches. © 1998 Academic Press