Packed compact tries: A fast and efficient data structure for online string processing

Takuya Takagi, Shunsuke Inenaga, Kunihiko Sadakane, Hiroki Arimura

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


We present a new data structure called the packed compact trie (packed c-trie) which stores a set S of k strings of total length n in n log + O(k log n) bits of space and supports fast pattern matching queries and updates, where is the alphabet size. Assume that = log n letters are packed in a single machine word on the standard word RAM model, and let f (k; n) denote the query and update times of the dynamic predecessor/successor data structure of our choice which stores k integers from universe [1; n] in O(k log n) bits of space. Then, given a string of length m, our packed c-tries support pattern matching queries and insert/delete operations in O( m f (k; n)) worst-case time and in O( m + f (k; n)) expected time. Our experiments show that our packed c-tries are faster than the standard compact tries (a.k.a. Patricia trees) on real data sets. We also discuss applications of our packed c-tries.

Original languageEnglish
Pages (from-to)1785-1793
Number of pages9
JournalIEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences
Issue number9
Publication statusPublished - Sept 2017

All Science Journal Classification (ASJC) codes

  • Signal Processing
  • Computer Graphics and Computer-Aided Design
  • Electrical and Electronic Engineering
  • Applied Mathematics


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