Copyright 2013, Michael H. Goldwasser Developed for use with the book: Data Structures and Algorithms in Python Michael T. Goodrich, Roberto Tamassia, and Michael H. Goldwasser John Wiley & Sons, 2013 This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>.