Memoryless Facility Location in One Pass

We present the first one-pass memoryless algorithm for metric Facility Location which maintains a set of facilities approximating the optimal facility configuration within a constant factor. The algorithm considers the demand points one-by-one in arbitrary order, is randomized and very simple to state and implement. It runs in linear time and keeps in memory only the facility locations currently open. We prove that its competitive ratio is less than 14 in the special case of uniform facility costs and less than 49 in the general case of non-uniform facility costs.