On Deletion in Threaded Binary Trees

Abstract We determine the explicit performance of deletion algorithms which have to maintain threads in a binary tree. In particular, it is shown that the cost of threads on deletion is not as high as might be expected, and is especially low for right-threaded trees. The results are obtained by using recurrences to compute the average cost of deleting a single node from both threaded and unthreaded trees. As an illustration of the technique, a new derivation of the average cost of insertion into binary search trees is presented.