Burrows-Wheeler transform. (a) The Burrows-Wheeler matrix and transformation for 'acaacg'. (b) Steps taken by EXACTMATCH to identify the range of rows, and thus the set of reference suffixes, prefixed by 'aac'. (c) UNPERMUTE repeatedly applies the last first (LF) mapping to recover the original text (in red on the top line) from the Burrows-Wheeler transform (in black in the rightmost column).
Langmead et al. Genome Biology 2009 10:R25 doi:10.1186/gb-2009-10-3-r25