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In this paper we analyze a hash function for $k$-partitioning a set into bins, obtaining strong concentration bounds for standard algorithms combining statistics from each bin. This generic method was originally introduced by Flajolet and…

Data Structures and Algorithms · Computer Science 2016-02-16 Søren Dahlgaard , Mathias Bæk Tejs Knudsen , Eva Rotenberg , Mikkel Thorup

The study of hashing is closely related to the analysis of balls and bins. It is well-known that instead of using a single hash function if we randomly hash a ball into two bins and place it in the smaller of the two, then this dramatically…

Data Structures and Algorithms · Computer Science 2007-05-23 Rina Panigrahy

Weighted minwise hashing (WMH) is one of the fundamental subroutine, required by many celebrated approximation algorithms, commonly adopted in industrial practice for large scale-search and learning. The resource bottleneck of the…

Data Structures and Algorithms · Computer Science 2016-02-29 Anshumali Shrivastava

Random hashing can provide guarantees regarding the performance of data structures such as hash tables---even in an adversarial setting. Many existing families of hash functions are universal: given two data objects, the probability that…

Data Structures and Algorithms · Computer Science 2018-10-16 Dmytro Ivanchykhin , Sergey Ignatchenko , Daniel Lemire

We consider bottom-k sampling for a set X, picking a sample S_k(X) consisting of the k elements that are smallest according to a given hash function h. With this sample we can estimate the relative size f=|Y|/|X| of any subset Y as |S_k(X)…

Data Structures and Algorithms · Computer Science 2013-06-12 Mikkel Thorup

In this paper, we analyze hashing from a worst-case perspective. To this end, we study a new property of hash families that is strongly related to d-perfect hashing, namely c-ideality. On the one hand, this notion generalizes the definition…

Data Structures and Algorithms · Computer Science 2023-02-01 Fabian Frei , David Wehner

A Perfect Hash Function (PHF) is a hash function that has no collisions on a given input set. PHFs can be used for space efficient storage of data in an array, or for determining a compact representative of each object in the set. In this…

Data Structures and Algorithms · Computer Science 2022-11-09 Hans-Peter Lehmann , Peter Sanders , Stefan Walzer

There is growing interest in representing image data and feature descriptors using compact binary codes for fast near neighbor search. Although binary codes are motivated by their use as direct indices (addresses) into a hash table, codes…

Computer Vision and Pattern Recognition · Computer Science 2014-04-28 Mohammad Norouzi , Ali Punjani , David J. Fleet

Given a collection of $m$ sets from a universe $\mathcal{U}$, the Maximum Set Coverage problem consists of finding $k$ sets whose union has largest cardinality. This problem is NP-Hard, but the solution can be approximated by a polynomial…

Data Structures and Algorithms · Computer Science 2023-12-13 Stephen Jaud , Anthony Wirth , Farhana Choudhury

We say a subset $C \subseteq \{1,2,\dots,k\}^n$ is a $k$-hash code (also called $k$-separated) if for every subset of $k$ codewords from $C$, there exists a coordinate where all these codewords have distinct values. Understanding the…

Information Theory · Computer Science 2018-05-14 Venkatesan Guruswami , Andrii Riazanov

We consider the hashing of a set $X\subseteq U$ with $|X|=m$ using a simple tabulation hash function $h:U\to [n]=\{0,\dots,n-1\}$ and analyse the number of non-empty bins, that is, the size of $h(X)$. We show that the expected size of…

Data Structures and Algorithms · Computer Science 2018-11-01 Anders Aamand , Mikkel Thorup

In multiple-choice data structures each element $x$ in a set $S$ of $m$ keys is associated with a random set $e(x) \subseteq [n]$ of buckets with capacity $\ell \geq 1$ by hash functions. This setting is captured by the hypergraph $H =…

Data Structures and Algorithms · Computer Science 2020-11-03 Stefan Walzer

We study the fundamental problem of approximate nearest neighbor search in $d$-dimensional Hamming space $\{0,1\}^d$. We study the complexity of the problem in the famous cell-probe model, a classic model for data structures. We consider…

Data Structures and Algorithms · Computer Science 2016-02-16 Mingmou Liu , Xiaoyin Pan , Yitong Yin

Secret sharing schemes create an effective method to safeguard a secret by dividing it among several participants. By using hash functions and the herding hashes technique, we first set up a (t+1, n) threshold scheme which is perfect and…

Cryptography and Security · Computer Science 2011-11-08 Chi Sing Chum , Xiaowen Zhang

Feature hashing, also known as {\em the hashing trick}, introduced by Weinberger et al. (2009), is one of the key techniques used in scaling-up machine learning algorithms. Loosely speaking, feature hashing uses a random sparse projection…

Machine Learning · Computer Science 2018-05-23 Casper Benjamin Freksen , Lior Kamma , Kasper Green Larsen

Explorable heap selection is the problem of selecting the $n$th smallest value in a binary heap. The key values can only be accessed by traversing through the underlying infinite binary tree, and the complexity of the algorithm is measured…

Data Structures and Algorithms · Computer Science 2024-09-12 Sander Borst , Daniel Dadush , Sophie Huiberts , Danish Kashaev

Previous work on tabulation hashing by Patrascu and Thorup from STOC'11 on simple tabulation and from SODA'13 on twisted tabulation offered Chernoff-style concentration bounds on hash based sums, e.g., the number of balls/keys hashing to a…

Data Structures and Algorithms · Computer Science 2020-08-11 Anders Aamand , Jakob B. T. Knudsen , Mathias B. T. Knudsen , Peter M. R. Rasmussen , Mikkel Thorup

This paper establishes the theoretical framework of b-bit minwise hashing. The original minwise hashing method has become a standard technique for estimating set similarity (e.g., resemblance) with applications in information retrieval,…

Data Structures and Algorithms · Computer Science 2009-10-20 Ping Li , Arnd Christian Konig

We propose an adaptive threshold multi secret sharing scheme based solely on cryptographically secure hash functions. We show that the proposed scheme is also: perfect, ideal, verifiable, and proactive. Moreover the proposed scheme has a…

Cryptography and Security · Computer Science 2023-02-07 M. Andrecut

In Linear Hashing ($\mathsf{LH}$) with $\beta$ bins on a size $u$ universe ${\mathcal{U}=\{0,1,\ldots, u-1\}}$, items $\{x_1,x_2,\ldots, x_n\}\subset \mathcal{U}$ are placed in bins by the hash function $$x_i\mapsto (ax_i+b)\mod p \mod…

Data Structures and Algorithms · Computer Science 2024-05-21 Alek Westover