Preserving order in a forest in less than logarithmic time
P. van Emde Boas · 1975
We present a data structure, based upon a stratified binary tree, which enables us to manipulate on-line a priority queue whose priorities are selected from the interval 1...n, with an average and worst case processing time of O(log log n) per instruction. The structure is used to obtain a mergeable heap whose time requirements are about as good.