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arXiv · 2604.21140

On Time-Memory Tradeoffs for Maximal Palindromes with Wildcards and $k$-Mismatches

Amihood Amir·Ayelet Butman·Michael Itzhaki·Dina Sokol
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Abstract

This paper addresses the problem of identifying palindromic factors in texts that include wildcards -- special characters that match all others. These symbols challenge many classical algorithms, as numerous combinatorial properties are not satisfied in their presence. We apply existing wildcard-LCE techniques to obtain a continuous time-memory tradeoff, and present the first non-trivial linear-space algorithm for computing all maximal palindromes with wildcards, improving the best known time-memory product in certain parameter ranges. Our main results are algorithms to find and approximate all maximal palindromes in a given text. We also generalize both methods to the $k$-mismatches setting, with or without wildcards.

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Amihood Amir, Ayelet Butman, Michael Itzhaki, Dina Sokol. 2026-04-22. On Time-Memory Tradeoffs for Maximal Palindromes with Wildcards and $k$-Mismatches. https://doi.org/10.4230/lipics.cpm.2026.2123

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