Date: Tue, 10 Dec 1996 21:21:42 GMT Server: NCSA/1.4.2 Content-type: text/html Last-modified: Mon, 04 Sep 1995 19:47:16 GMT Content-length: 3084 Upper and Lower Bounds on Constructing Alphabetic Binary Trees



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Upper and Lower Bounds on Constructing Alphabetic Binary Trees

MARIA KLAWEgif and BRENDAN MUMEYgif

Abstract:

This paper studies the long-standing open question of whether optimal alphabetic binary trees can be constructed in time. We show that a class of techniques for finding optimal alphabetic trees which includes all current methods yielding time algorithms are at least as hard as sorting in whatever model of computation is used. We also give time algorithms for the case where all the input weights are within a constant factor of one another and when they are exponentially separated.





Brendan Mumey
Mon Sep 4 11:52:47 PDT 1995