Tree Compression with Top Trees Revisited
- Cite this paper as:
- Hübschle-Schneider L., Raman R. (2015) Tree Compression with Top Trees Revisited. In: Bampis E. (eds) Experimental Algorithms. SEA 2015. Lecture Notes in Computer Science, vol 9125. Springer, Cham
We revisit tree compression with top trees (Bille et al. ), and present several improvements to the compressor and its analysis. By significantly reducing the amount of information stored and guiding the compression step using a RePair-inspired heuristic, we obtain a fast compressor achieving good compression ratios, addressing an open problem posed by . We show how, with relatively small overhead, the compressed file can be converted into an in-memory representation that supports basic navigation operations in worst-case logarithmic time without decompression. We also show a much improved worst-case bound on the size of the output of top-tree compression (answering an open question posed in a talk on this algorithm by Weimann in 2012).
KeywordsTree compression Grammar compression Top trees XML compression
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