/**
   * BSD-licensed Java implementation of "An O(ND) Difference Algorithm 
   * and its Variations" by Eugene Myers, published in
   * Algorithmica Vol. 1 No. 2, 1986, p 251.
   * 
   * C# version written by Mathias Hertel, http://www.mathertel.de
   * Mathias Hertel's version ported to Java by Ian Darwin, http://www.darwinsys.com/
   */