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The repetition-free longest common subsequence problem

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Author(s):
Christian Tjandraatmadja
Total Authors: 1
Document type: Master's Dissertation
Press: São Paulo.
Institution: Universidade de São Paulo (USP). Instituto de Matemática e Estatística (IME/SBI)
Defense date:
Examining board members:
Carlos Eduardo Ferreira; Marie France Sagot; Yoshiko Wakabayashi
Advisor: Carlos Eduardo Ferreira
Abstract

We explore the following problem: given two sequences X and Y over a finite alphabet, find a longest common subsequence of X and Y without repeated symbols. We study the structure of this problem, particularly from the point of view of graphs and polyhedral combinatorics. We develop approximation algorithms and heuristics for this problem. The focus of this work is in the construction of an algorithm based on the branch-and-cut technique, taking advantage of an efficient separation algorithm and of heuristics and techniques to find an optimal solution earlier. We also study an easier problem on which this problem is based: given two sequences X and Y over a finite alphabet, find a longest common subsequence of X and Y. We explore this problem from the point of view of polyhedral combinatorics and describe several known algorithms to solve it. (AU)