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arXiv · 1702.06256

A $(1.4 + \epsilon)$-approximation algorithm for the $2$-Max-Duo problem

Yao Xu·Yong Chen·Guohui Lin·Tian Liu·Taibo Luo·Peng Zhang
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Abstract

The maximum duo-preservation string mapping (Max-Duo) problem is the complement of the well studied minimum common string partition (MCSP) problem, both of which have applications in many fields including text compression and bioinformatics. $k$-Max-Duo is the restricted version of Max-Duo, where every letter of the alphabet occurs at most $k$ times in each of the strings, which is readily reduced into the well known maximum independent set (MIS) problem on a graph of maximum degree $\Delta \le 6(k-1)$. In particular, $2$-Max-Duo can then be approximated arbitrarily close to $1.8$ using the state-of-the-art approximation algorithm for the MIS problem. $2$-Max-Duo was proved APX-hard and very recently a $(1.6 + \epsilon)$-approximation was claimed, for any $\epsilon > 0$. In this paper, we present a vertex-degree reduction technique, based on which, we show that $2$-Max-Duo can be approximated arbitrarily close to $1.4$.

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Yao Xu, Yong Chen, Guohui Lin, Tian Liu, Taibo Luo, Peng Zhang. 2017-02-21. A $(1.4 + \epsilon)$-approximation algorithm for the $2$-Max-Duo problem. https://arxiv.org/abs/1702.06256

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