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Re-Pair In Small Space
- Publication Year :
- 2019
-
Abstract
- Re-Pair is a grammar compression scheme with favorably good compression rates. The computation of Re-Pair comes with the cost of maintaining large frequency tables, which makes it hard to compute Re-Pair on large scale data sets. As a solution for this problem we present, given a text of length $n$ whose characters are drawn from an integer alphabet, an $O(n^2) \cap O(n^2 \lg \log_\tau n \lg \lg \lg n / \log_\tau n)$ time algorithm computing Re-Pair in $n \lg \max(n,\tau)$ bits of space including the text space, where $\tau$ is the number of terminals and non-terminals. The algorithm works in the restore model, supporting the recovery of the original input in the time for the Re-Pair computation with $O(\lg n)$ additional bits of working space. We give variants of our solution working in parallel or in the external memory model.
- Subjects :
- Computer Science - Data Structures and Algorithms
Subjects
Details
- Database :
- arXiv
- Publication Type :
- Report
- Accession number :
- edsarx.1908.04933
- Document Type :
- Working Paper