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Block Sorting: A New Characterization and a New Heuristic

Authors: Swapnoneel Roy, Ashok Kumar Thakur, Minhazur Rahman


The Block Sorting problem is to sort a given permutation moving blocks. A block is defined as a substring of the given permutation, which is also a substring of the identity permutation. Block Sorting has been proved to be NP-Hard. Until now two different 2-Approximation algorithms have been presented for block sorting. These are the best known algorithms for Block Sorting till date. In this work we present a different characterization of Block Sorting in terms of a transposition cycle graph. Then we suggest a heuristic, which we show to exhibit a 2-approximation performance guarantee for most permutations.

Keywords: Optical Character Recognition, Genome Rearrangements, Sorting Primitives, Block Sorting, ApproximationAlgorithms

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