Abstract

We consider open addressing hashing and implement it by using the Robin Hood strategy; that is, in case of collision, the element that has traveled the farthest can stay in the slot. We hash ∼ αn elements into a table of size n where each probe is independent and uniformly distributed over the table, and α<1 is a constant. Let Mn be the maximum search time for any of the elements in the table. We show that with probability tending to one, Mn ∈ [log 2 log n + σ, log 2 log n + τ] for some constants σ, τ depending upon α only. This is an exponential improvement over the maximum search time in case of the standard FCFS (first come first served) collision strategy and virtually matches the performance of multiple-choice hash methods.

Citations