Range‐Efficient Counting of Distinct Elements in a Massive Data Stream
نویسندگان
چکیده
منابع مشابه
Counting Distinct Elements in a Data Stream
We present three algorithms to count the number of distinct elements in a data stream to within a factor of 1 ± ǫ. Our algorithms improve upon known algorithms for this problem, and offer a spectrum of time/space tradeoffs.
متن کاملRange-Efficient Counting of Distinct Elements in a Massive Data Stream
Efficient one-pass estimation of F0, the number of distinct elements in a data stream, is a fundamental problem arising in various contexts in databases and networking. We consider rangeefficient estimation of F0: estimation of the number of distinct elements in a data stream where each element of the stream is not just a single integer but an interval of integers. We present a randomized algor...
متن کاملRange-Efficient Counting of Distinct Elements in a Massive Data
Efficient one-pass estimation of F0, the number of distinct elements in a data stream, is a fundamental problem arising in various contexts in databases and networking. We consider range-efficient estimation of F0: estimation of the number of distinct elements in a data stream where each element of the stream is not just a single integer, but an interval of integers. We present a randomized alg...
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We prove Ω(n) deterministic lower bounds for any streaming algorithm that exactly computes the number of inversions (2-dec-count) in a data stream of t elements where each element comes from [n] and t ≥ Ω(n). The proof uses a reduction argument and utilizes communication lower bounds for computation of disjointness. Our second result is Ω(n) lower bound on any algorithm that correctly computes ...
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In this paper we classify fuzzy subgroups of a rank-3 abelian group $G = mathbb{Z}_{p^n} + mathbb{Z}_p + mathbb{Z}_p$ for any fixed prime $p$ and any positive integer $n$, using a natural equivalence relation given in cite{mur:01}. We present and prove explicit polynomial formulae for the number of (i) subgroups, (ii) maximal chains of subgroups, (iii) distinct fuzzy subgroups, (iv) non-isomorp...
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ژورنال
عنوان ژورنال: SIAM Journal on Computing
سال: 2007
ISSN: 0097-5397,1095-7111
DOI: 10.1137/050643672