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An Optimal Algorithm for Generating Minimal Perfect Hash Functions
 Information Processing Letters
, 1992
"... A new algorithm for generating order preserving minimal perfect hash functions is presented. The algorithm is probabilistic, involving generation of random graphs. It uses expected linear time and requires a linear number words to represent the hash function, and thus is optimal up to constant facto ..."
Abstract

Cited by 42 (0 self)
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A new algorithm for generating order preserving minimal perfect hash functions is presented. The algorithm is probabilistic, involving generation of random graphs. It uses expected linear time and requires a linear number words to represent the hash function, and thus is optimal up to constant factors. It runs very fast in practice. Keywords: Data structures, probabilistic algorithms, analysis of algorithms, hashing, random graphs
Finding Succinct Ordered Minimal Perfect Hash Functions
, 1994
"... An ordered minimal perfect hash table is one in which no collisions occur among a predefined set of keys, no space is unused and the data are placed in the table in order. A new method for creating ordered minimal perfect hash functions is presented. It creates hash functions with representation spa ..."
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Cited by 1 (0 self)
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An ordered minimal perfect hash table is one in which no collisions occur among a predefined set of keys, no space is unused and the data are placed in the table in order. A new method for creating ordered minimal perfect hash functions is presented. It creates hash functions with representation space requirements closer to the theoretical lower bound than previous methods. The method presented requires approximately 17% less space to represent generated hash functions and is easy to implement. However, a high time complexity makes it practical for small sets only (size ! 1000). Keywords: Data Structures, Hashing, Perfect Hashing 1 Introduction A hash table is a data structure in which a number of keyed items are stored. To access an item with a given key, a hash function is used. The hash function maps from the set of keys, to the set of locations of the table. If more than one key maps to a given location, a collision occurs, and some collision resolution policy must be followed. O...
An Application Of Elisa To Perfect Hashing With Deterministic Ordering
"... This paper describes a practical application of a novel terminal attractor algorithm to the construction of Perfect Hash Functions (PHF) for a predefined set of keys. The proposed method, which can be used in the ordering phase of a classical Mapping, Deterministic Ordering and Searching (MDOS) appr ..."
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This paper describes a practical application of a novel terminal attractor algorithm to the construction of Perfect Hash Functions (PHF) for a predefined set of keys. The proposed method, which can be used in the ordering phase of a classical Mapping, Deterministic Ordering and Searching (MDOS) approach, is based on a neural network canonical form of efficient gradient descent, for solving linear systems, named ELISA. Numerical experiments clearly show that ELISA is able to determine the optimal solution in many difficult cases, where other alternative algorithms fail or are ineffective.