 
Summary: Text Indexing and Dictionary Matching with One Error \Lambda
Amihood Amir yz Dmitry Keselman x Gad M. Landau 
BarIlan University Simons Technologies Haifa University
and and
Georgia Tech Polytechnic University
Moshe Lewenstein y k Noa Lewenstein y \Lambda\Lambda Michael Rodeh yy
BarIlan University BarIlan University IBM Research
Abstract
The indexing problem is the one where a text is preprocessed and subsequent queries of the
form: ``Find all occurrences of pattern P in the text'' are answered in time proportional to the
length of the query and the number of occurrences. In the dictionary matching problem a set of
patterns is preprocessed and subsequent queries of the form: ``Find all occurrences of dictionary
patterns in text T '' are answered in time proportional to the length of the text and the number
of occurrences.
There exist efficient worstcase solutions for the indexing problem and the dictionary match
ing problem, but none that find approximate occurrences of the patterns, i.e. where the pattern
is within a bound edit (or Hamming) distance from the appropriate text location.
In this paper we present a uniform deterministic solution to both the indexing and the general
dictionary matching problem with one error. We preprocess the data in time O(n log 2
n), where
