Document Type

Technical Report

Publication Date

3-1994

Technical Report Number

PCS-TR94-206

Abstract

We present here an algorithm for detecting (and outputting, if exists) a negative cycle in an $n$-vertex planar digraph $G$ with real edge weights. Its running time ranges from $O(n)$ up to $O(n^{1.5}\log n)$ as a certain topological measure of $G$ varies from $1$ up to $\Theta(n)$. Moreover, an efficient CREW PRAM implementation is given. Our algorithm applies also to digraphs whose genus $\gamma$ is $o(n)$.

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