We propose a storage scheme for a string S[1, n], drawn from an alphabet Σ, that requires space close to the k-th order empirical entropy of S, and allows to retrieve any ℓ-long substring of S in optimal O(1 + ℓ/log|Σ| n) time. This matches the best known bounds, via the use of binary encodings and tables only. We also apply this storage scheme to prove new time vs space trade-offs for compressed self indexes and the Burrows-Wheeler Transform.
A simple storage scheme for strings achieving entropy bounds
FERRAGINA, PAOLO;VENTURINI, ROSSANO
2007-01-01
Abstract
We propose a storage scheme for a string S[1, n], drawn from an alphabet Σ, that requires space close to the k-th order empirical entropy of S, and allows to retrieve any ℓ-long substring of S in optimal O(1 + ℓ/log|Σ| n) time. This matches the best known bounds, via the use of binary encodings and tables only. We also apply this storage scheme to prove new time vs space trade-offs for compressed self indexes and the Burrows-Wheeler Transform.File in questo prodotto:
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