Faster Average Case Low Memory Semi-External Construction of the Burrows-Wheeler Transform

The Burrows Wheeler transform has applications in data compression as well as full text indexing. Despite its important applications and various existing algorithmic approaches the construction of the transform for large data sets is still challenging. In this paper we present a new semi external memory algorithm capable of constructing the transform in time O(n log2 log n) on average if su cient internal memory is available to hold a fixed fraction of the input text. In the worst case the run-time is O(n log n log log n).