An optimal algorithm for the on-line closest-pair problem

Abstract

We give an algorithm that computes the closest pair in a set of $n$ points in $k$-dimensional space on-line, in $O(n \log n)$ ime. The algorithm only uses algebraic functions and, therefore, is optimal. The algorithm maintains a hierarchical subdivision of $k$-space into hyperrectangles, which is stored in a binary tree. Centroids are used to maintain a balanced decomposition of this tree