preface is far too brief to be used in such course you might find it useful to use an additional work on np-completeness to augment this text exercises exercisesprovided at the end of each match the order in which material is presented the last exercises may address the as whole rather than specific section difficult exercises are marked with an asteriskand more challenging exercises have two asterisks references references are placed at the end of each generally the references either are historicalrepresenting the original source of the materialor they represent extensions and improvements to the results given in the text some references represent solutions to exercises supplements the following supplements are available to all readers at source code for example programs errata in additionthe following material is available only to qualified instructors at pearson instructor resource center (www pearsonhighered com/ircvisit the irc or contact your pearson education sales representative for access solutions to selected exercises figures from the book errata acknowledgments manymany people have helped me in the preparation of books in this series some are listed in other versions of the bookthanks to all as usualthe writing process was made easier by the professionals at pearson ' like to thank my editortracy johnsonand production editormarilyn lloyd my wonderful wife jill deserves extra special thanks for everything she does finallyi' like to thank the numerous readers who have sent -mail messages and pointed out errors or inconsistencies in earlier versions my website www cis fiu edu/~weiss will also contain updated source code (in +and java)an errata listand link to submit bug reports miamiflorida