Journal ArticleDOI
Storing a Sparse Table with 0(1) Worst Case Access Time
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A data structure for representing a set of n items from a universe of m items, which uses space n+o(n) and accommodates membership queries in constant time and is easy to implement.Abstract:
A data structure for representing a set of n items from a umverse of m items, which uses space n + o(n) and accommodates membership queries m constant time is described. Both the data structure and the query algorithm are easy to ~mplement.read more
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Lower bounds in the quantum cell probe model
Pranab Sen,S. Venkatesh +1 more
TL;DR: In this article, a lower bound for the predecessor problem in the classical cell probe model with randomised query schemes was shown, which matches the classical deterministic upper bound of Beame and Fich.
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Algorithmic complexity of protein identification: combinatorics of weighted strings
TL;DR: In this paper, the problem of finding an efficient data structure and query algorithm for a constant-size alphabet with a weight function was investigated and two algorithms were proposed: L OOKUP and I NTERVAL for binary alphabets with O( n ) storage space and O( log n) query time.
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Pattern Matching and Consensus Problems on Weighted Sequences and Profiles
TL;DR: This work proposes algorithms for the consensus problem parameterised by the number of strings that match one of the sequences, and proves that their dependence on the parameter is optimal up to lower-order terms conditioned on the optimality of the original algorithm for the knapsack problem.
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Alignment-free sequence comparison using absent words
TL;DR: In this paper, a linear-time and linear-space algorithm was proposed to compare two sequences by considering all their minimal absent words, where a word is an absent word of some sequence if it does not occur in the sequence.
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Two results on tables
TL;DR: The first result is an improvement of the optimal program size for perfect hash functions, solving an open problem from Slot and Van Emde Boas (1984): for every value u, value k ⩽ u, and every subset A of U there exists a perfect hash function F which scatters A completely into a hash table of size O(k), such that the program size is O( k·log log k + log log u) and the evaluation time of F is O (1
References
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Journal ArticleDOI
Should Tables Be Sorted
TL;DR: It is shown that, in a rather general model including al1 the commonly-used schemes, $\lceil $ lg(n+l) $\rceil$ probes to the table are needed in the worst case, provided the key space is sufficiently large.
Journal ArticleDOI
Storing a sparse table
TL;DR: This work proposes a good worst-case method for storing a static table of n entries, each an integer between 0 and N - 1, and analysis shows why a simpler algorithm used for compressing LR parsing tables works so well.
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Perfect hashing functions: a single probe retrieving method for static sets
TL;DR: A refinement of hashing which allows retrieval of an item in a static table with a single probe is considered, and a rough comparison with ordinary hashing is given which shows that this method can be used conveniently in several practical applications.
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Reciprocal hashing: a method for generating minimal perfect hashing functions
TL;DR: A method is presented for building minimal perfect hash functions, i.e., functions which allow single probe retrieval from minimally sized tables of identifier sets, and a proof of existence for minimalperfect hash functions of a special type (reciprocal type) is given.