A Letter-oriented Minimal Perfect Hashing Scheme

نویسندگان

چکیده

برای دانلود رایگان متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

A Letter-oriented Perfect Hashing Scheme Based upon Sparse Table Compression

In this paper, a new letter-oriented perfect hashing scheme based on Ziegler’s row displacement method is presented. A unique n -tuple from a given set of static letter-oriented key words can be extracted by a heuristic algorithm. Then the extracted distinct n -tuples are associated with a 0/1 sparse matrix. Using a sparse matrix compression technique, a perfect hashing function on the key word...

متن کامل

A Practical Minimal Perfect Hashing Method

We propose a novel algorithm based on random graphs to construct minimal perfect hash functions h. For a set of n keys, our algorithm outputs h in expected time O(n). The evaluation of h(x) requires two memory accesses for any key x and the description of h takes up 1.15n words. This improves the space requirement to 55% of a previous minimal perfect hashing scheme due to Czech, Havas and Majew...

متن کامل

Application of Minimal Perfect Hashing in Main Memory Indexing

With the rapid decrease in the cost of random access memory (RAM), it will soon become economically feasible to place full-text indexes of a library in main memory. One essential component of the indexing system is a hashing algorithm, which maps a keyword into the memory address of the index information corresponding to that keyword. This thesis studies the application of the minimal perfect h...

متن کامل

Theory and Practise of Monotone Minimal Perfect Hashing

Minimal perfect hash functions have been shown to be useful to compress data in several data management tasks. In particular, order-preservingminimal perfect hash functions [12] have been used to retrieve the position of a key in a given list of keys: however, the ability to preserve any given order leads to an unavoidable (n log n) lower bound on the number of bits required to store the funct...

متن کامل

Perfect Hashing with Pseudo-minimal Bottom-up Deterministic Tree Automata

We describe a technique that maps unranked trees to their hash codes using a bottom-up deterministic tree automaton (DTA). In contrast to techniques implemented with minimal tree automata, our procedure builds a pseudo-minimal DTA. Pseudo-minimal automata are larger than the minimal ones but in turn the mapping can be arbitrary, so it can be determined prior to the automaton construction. We al...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

ژورنال

عنوان ژورنال: The Computer Journal

سال: 1986

ISSN: 0010-4620,1460-2067

DOI: 10.1093/comjnl/29.3.277