Performance of Height-Balanced Trees This paper presents the results of simulations that investigate the performance of height-balanced (HB[k]) trees. It is shown that the only statistic of HB[1] trees (AVL trees) that is a function of the size of the tree is the time to search for an item in the tree. For sufficiently large trees, the execution times of all procedures for maintaining HB[1] trees are independent of the size of the tree. In particular, an average of .465 restructures are required per insertion, with an average of 2.78 nodes revisited to restore the HB[1] property; an average of .214 restructures are required per deletion, with an average of 1.91 nodes revisited to restore the HB[1] property. Moreover,the execution times of procedures for maintaining HB[k] trees, for k>1, are also independent of the size of the tree except for the average number of nodes revisited on a delete operation in order to restore the HB[k] property on trace back. The cost of maintaining HB[k] trees drops sharply as the allowable imbalance (k) increases. Both analytical and experimental results that show the cost of maintaining HB[k] trees as a function of k are discussed. CACM January, 1976 Karlton, P. L. Fuller, S. H. Scroggs, R. E. Kaehler, E. B. HB[k] trees, balanced trees, AVL trees, information storage and retrieval, searching 3.7 3.72 3.74 4.49 5.39 CA760104 JB January 5, 1978 10:27 AM 2411 4 2889 2455 4 2889 2493 4 2889 2709 4 2889 2889 4 2889 2889 4 2889 2889 4 2889 2937 4 2889 2968 4 2889 2968 4 2889 2989 4 2889 3005 4 2889 3025 4 2889 3042 4 2889 3101 4 2889 2138 5 2889 2388 5 2889 2455 5 2889 2839 5 2889 2889 5 2889 2889 5 2889 2889 5 2889 3042 5 2889 3096 5 2889 3163 5 2889 2455 6 2889 2839 6 2889 2839 6 2889 2839 6 2889 2889 6 2889 2889 6 2889 2889 6 2889 2889 6 2889 2968 6 2889 3009 6 2889 3009 6 2889 3065 6 2889 3096 6 2889