Abstract

We introduce the first index that can be built in o(n) time for a text of length n, and can also be queried in o(q) time for a pattern of length q. On an alphabet of size, our index uses O(n log) bits, is built in O(n log f/plog n) deterministic time, and computes the number of occurrences of the pattern in time O(q/logf n+log n logf n). Each such occurrence can then be found in O(log n) time. Other trade-offs between the space usage and the cost of reporting occurrences are also possible. 2012 ACM Subject Classification Theory of computation ! Data structures design and analysis.