1 citations · 1 across the 11 of their papers we have counts for
12 papers
Disproving the Greedy Superstring Conjecture
Hiroki Shibata
The shortest common superstring problem is to find the shortest string that contains every string in a given set as a substring. It is conjectured that the greedy algorithm that re…
Sensitivity and Size Relationships of the Lempel-Ziv Factorization
Hiroki Shibata, Yuto Fujie
The Lempel-Ziv (LZ) factorization is a fundamental method for compressing repetitive strings. Its multiplicative sensitivity to an operation measures how much that operation can in…
Compact Enumeration of Maximal Closed Substrings in Run-Length Encoded Strings
Haruki Umezaki, Hiroki Shibata, Yuto Nakashima +1
A string is closed if , or if has a non-empty proper border occurring only as its prefix and suffix. A maximal closed substring (MCS) is a maximal occurrence of a cl…
Online computation of maximal closed substrings
Hiroki Shibata, Haruki Umezaki, Takuya Mieno +2
A non-empty string is closed if it has length one or its longest border appears exactly twice in the string. An occurrence of a closed substring is a maximal closed substring (MCS)…
Relaxation of Square-Freeness
Hiroki Shibata, Takuya Mieno, Dominik Köppl +1
We extend the analysis of nonrepetitive sequences of Entringer et al. [Journal of Combinatorial Theory, 1974] to relaxations of equality testing under nonstandard equivalence relat…
String Representation Based on Substring Equation Systems
Hiroki Shibata, Hideo Bannai
Repetitiveness measures quantify how much repetitive structure a string contains and serve as parameters for compressed representations and indexing data structures. Many compressi…
Online Computation of Palindromes and Suffix Trees on Tries
Hiroki Shibata, Mitsuru Funakoshi, Takuya Mieno +5
We consider the problems of computing maximal palindromes and distinct palindromes in a trie. A trie is a natural generalization of a string, which can be seen as a single-path tre…
Tight Additive Sensitivity on LZ-style Compressors and String Attractors
Yuto Fujie, Hiroki Shibata, Yuto Nakashima +1
The worst-case additive sensitivity of a string repetitiveness measure is defined to be the largest difference between and , where is a string of length a…
Counting Distinct (Non-)Crossing Substrings in Optimal Time
Haruki Umezaki, Hiroki Shibata, Dominik Köppl +3
Let be a string of length . The problem of counting factors crossing a position -- Problem 64 from the textbook ``125 Problems in Text Algorithms'' [Crochemore, Lecroq, and…
LZBE: an LZ-style compressor supporting -time random access
Hiroki Shibata, Yuto Nakashima, Yutaro Yamaguchi +1
An LZ-like factorization of a string divides it into factors, each being either a single character or a copy of a preceding substring. While grammar-based compression schemes suppo…
Packed Acyclic Deterministic Finite Automata
Hiroki Shibata, Masakazu Ishihata, Shunsuke Inenaga
An acyclic deterministic finite automaton (ADFA) is a data structure that represents a set of strings (i.e., a dictionary) and facilitates a pattern searching problem of determinin…
Subsequence Matching and LCS under Cartesian-Tree Equivalence
Taketo Tsujimoto, Yuki Yonemoto, Hiroki Shibata +3
Two strings of the same length are said to Cartesian-tree match (CT-match) if their Cartesian-trees are isomorphic [Park et al., TCS 2020]. Cartesian-tree matching is a natural mod…