On Dynamic Breadth-First Search in External-Memory

Abstract

We provide the first non-trivial result on dynamic breadth-first search (BFS) in external-memory: For general sparse undirected graphs of initially n nodes and O(n) edges and monotone update sequences of either (n) edge insertions or (n) edge deletions, we prove an amortized high-probability bound of O(n/B2/3+(n)· B) I/Os per update. In contrast, the currently best approach for static BFS on sparse undirected graphs requires (n/B1/2+(n)) I/Os.