Fast BWT in small space by blockwise suffix sorting

The usual way to compute the Burrows–Wheeler transform (BWT) [3] of a text is by constructing the suffix array of the text. Even with space-efficient suffix array construction algorithms [12, 2], the space requirement of the suffix array itself is often the main factor limiting the size of the text that can be handled in one piece, which is crucial for constructing compressed text indexes [4, 5]. Typically, the suffix array needs 4n bytes while the text and the BWT need only n bytes each and sometimes even less, for example 2n bits each for a DNA sequence. We reduce the space dramatically by constructing the suffix array in blocks of lexicographically consecutive suffixes. Given such a block, the corresponding block of the BWT is trivial to compute.