Given a string S of length n, the classic string indexing problem is to preprocess S into a compact data structure that supports efficient subsequent pattern queries. In this paper we consider the basic variant where the pattern is given in compressed form and the goal is to achieve query time that is fast in terms of the compressed size of the pattern. This captures the common client-server scenario, where a client submits a query and communicates it in compressed form to a server. Instead of the server decompressing the query before processing it, we consider how to efficiently process the compressed query directly. Our main result is a novel linear space data structure that achieves near-optimal query time for patterns compressed with the classic Lempel-Ziv 1977 (LZ77) compression scheme. Along the way we develop several data structural techniques of independent interest, including a novel data structure that compactly encodes all LZ77 compressed suffixes of a string in linear space and a general decomposition of tries that reduces the search time from logarithmic in the size of the trie to logarithmic in the length of the pattern.

给定长度为n的字符串S，经典的字符串索引问题是预处理S转换为紧凑的数据结构，支持高效的后续模式查询。在本文中，我们考虑基本变体，其中模式以压缩形式给出，目标是在模式的压缩大小方面实现快速的查询时间。这捕获了常见的客户端-服务器场景，其中客户端提交查询并将其以压缩形式传送到服务器。我们考虑如何直接有效地处理压缩的查询，而不是服务器在处理查询之前解压缩查询。我们的主要成果是一种新颖的线性空间数据结构，对于使用经典 Lempel-Ziv 1977 (LZ77) 压缩方案压缩的模式实现了近乎最佳的查询时间。一路上我们开发了几种独立感兴趣的数据结构技术，