Alphabetic Tree Problem: Difference between revisions

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(Created page with "{{DISPLAYTITLE:Alphabetic Tree Problem (Optimal Binary Search Trees)}} == Description == A variant of the OBST problem is when only the gaps have nonzero access probabilities, and is called the optimal alphabetic tree problem. == Related Problems == Generalizations: Optimal Binary Search Tree Problem Related: Approximate OBST, Huffman Encoding == Parameters == <pre>n: number of elements</pre> == Table of Algorithms == {| class="wikitable sortable"...")
 
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== Parameters ==  
== Parameters ==  


<pre>n: number of elements</pre>
n: number of elements


== Table of Algorithms ==  
== Table of Algorithms ==  

Revision as of 12:02, 15 February 2023

Description

A variant of the OBST problem is when only the gaps have nonzero access probabilities, and is called the optimal alphabetic tree problem.

Related Problems

Generalizations: Optimal Binary Search Tree Problem

Related: Approximate OBST, Huffman Encoding

Parameters

n: number of elements

Table of Algorithms

Name Year Time Space Approximation Factor Model Reference
Klawe; Mumey 1993 $O(n)$ $O(n)$ Exact Deterministic Time
Garsia–Wachs algorithm 1977 $O(n \log n)$ $O(n)$ Exact Deterministic Time & Space
Hu–Tucker algorithm 1971 $O(n \log n)$ $O(n)$ Exact Deterministic Time & Space

Time Complexity graph

Optimal Binary Search Trees - Alphabetic Tree Problem - Time.png

Space Complexity graph

Optimal Binary Search Trees - Alphabetic Tree Problem - Space.png

Pareto Decades graph

Optimal Binary Search Trees - Alphabetic Tree Problem - Pareto Frontier.png