preface others at prentice hall who helped me along the way include truly donovanlinda behrensand phyllis bregman am sure owe thanks to many others at prentice hall for their help in ways that am not even aware of wish to express my appreciation to hanan samet for teaching me about data structures learned much of the philosophy presented here from him as wellthough he is not responsible for any problems with the result thanks to my wife terryfor her love and supportand to my daughters irena and kate for pleasant diversions from working too hard finallyand most importantlyto all of the data structures students over the years who have taught me what is important and what should be skipped in data structures courseand the many new insights they have provided this book is dedicated to them clifford shaffer blacksburgvirginia