Deterministic Global Minimum Cut Using $\tilde{O}(n^{3/2})$ Cut Queries

Abstract

Finding a global minimum cut in an unweighted graph is a fundamental task in the cut-query model. While there exists a randomized algorithm for this task using $\tilde O(n)$ queries, known deterministic algorithms use $\tilde{O}(n^{5/3})$ queries. We improve upon this result and give a simple deterministic algorithm that finds a global minimum cut using $\tilde O(\min\left\{ nδ,n^2/δ\right\})$ cut queries, which equals $\tilde{O}(n^{3/2})$ in the worst case, where $δ$ is the minimum degree of the graph. The key ingredient in our approach is an efficient maximum $s,t$-flow algorithm, for the case when the minimum $s,t$-cut has value at most $δ$.