We present the first fully dynamic algorithm for maintaining all pairs shortest paths in directed graphs with real-valued edge weights. Given a dynamic directed graph G such that each edge can assume at most S different real values, we show how to support updates deterministically in O(S·n2.5log3n) amortized time and queries in optimal worst-case time. No previous fully dynamic algorithm was known for this problem. In the special case where edge weights can only be increased, we give a randomized algorithm with one-sided error which supports updates faster in O(S·nlog3n) amortized time.
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Foundations of Computer Science, 2001. Proceedings. 42nd IEEE Symposium on
Date of Conference: 8-11 Oct. 2001