Now showing items 1-20 of 30

  • Analysis of an optimized search algorithm for skip lists 

    Martínez Parra, Conrado (1994-03)
    External research report
    Open Access
    It was suggested in Pugh's Skip List Cookbook to avoid redundant queries in the skip list search algorithm by marking those elements whose key had already been checked by the search algorithm. We present here a precise ...
  • Analysis of Hoare's FIND algorithm with median-of-three partition 

    Kirschenhofer, P; Martínez Parra, Conrado; Prodinger, H (1995-02)
    External research report
    Open Access
    Hoare's Find algorithm can be used to select the jth element out of a file of n elements. It bears a remarkable similarity to Quicksort; in each pass of the algorithm, a pivot element is used to split the file into two ...
  • Analysis of pivot sampling in dual-pivot Quicksort: A holistic analysis of Yaroslavskiy's partitioning scheme 

    Nebel, Markus E.; Wild, Sebastian; Martínez Parra, Conrado (2016-08)
    Article
    Open Access
    The new dual-pivot Quicksort by Vladimir Yaroslavskiy-used in Oracle's Java runtime library since version 7-features intriguing asymmetries. They make a basic variant of this algorithm use less comparisons than classic ...
  • Analysis of quickfind with small subfiles 

    Martínez Parra, Conrado; Panario, Daniel; Viola Deambrosis, Alfredo (2001-11)
    External research report
    Open Access
    In this paper we investigate the variants of the well-known Hoare's Quickfind algorithm for the selection of the j-th element out of n, when recursion stops for subfiles whose size is below a predefined threshold and a ...
  • Analysis of the strategy "Hiring above the alpha-quantile" 

    Helmiy, Ahmed; Martínez Parra, Conrado; Panholzer, Alois (2012-11)
    External research report
    Open Access
    We study here the strategy hiring above the α-quantile of the hired staff. This strategy was introduced first by Archibald and Martınez in 2009. We show here more results like lower and upper bounds for many interesting ...
  • An Efficient generic algorithm for the generation of unlabelled cycles 

    Martínez Parra, Conrado; Molinero Albareda, Xavier (2003-06-06)
    External research report
    Open Access
    In this report we combine two recent generation algorithms to obtain a new algorithm for the generation of unlabelled cycles. Sawada's algorithm lists all k-ary unlabelled cycles with fixed content, that is, the number ...
  • A Top-down design of a parallel dictionary using skip lists 

    Gabarró Vallès, Joaquim; Martínez Parra, Conrado; Messeguer Peypoch, Xavier (1994-02)
    External research report
    Open Access
    We present a top down design of a parallel PRAM dictionary using skip lists. More precisely, we give algorithms to search, insert or delete k elements in a skip list of n elements, in parallel. The algorithms are simple ...
  • Elaboració d’un pla de tutories per a la FIB 

    Mora Giné, Mercè; Castell Ariño, Núria; Fernández Ruzafa, José; Herrero Zaragoza, José Ramón; Sánchez Carracedo, Fermín; Martínez Parra, Conrado; Nonell i Torrent, Ramon; Raventós Pagès, Ruth; Rius Carrasco, Roser (Universitat Politècnica de Catalunya. Institut de Ciències de l'Educació, 2013-02-08)
    Conference report / Conference lecture
    Open Access
    La majoria d'estudiants que accedeixen a la universitat, i en concret a la FIB, no són conscients del que comporta cursar una carrera universitària. Els estudis universitaris requereixen molta dedicació. Sovint els ...
  • Fixed partial match queries in quadtrees 

    Duch Brown, Amalia; Lau Laynes-Lozada, Gustavo Salvador; Martínez Parra, Conrado (Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2018)
    Conference report
    Open Access
    Several recent papers in the literature have addressed the analysis of the cost P_{n,q} of partial match search for a given fixed query q - that has s out of K specified coordinates - in different multidimensional data ...
  • Generic algorithms for the generation of combinatorial objects 

    Molinero Albareda, Xavier; Martínez Parra, Conrado (2003-06)
    External research report
    Open Access
    This report briefly describes our generic approach to the exhaustive generation of unlabelled and labelled combinatorial classes. Our algorithms receive a size n and a finite description of a combinatorial class A using ...
  • Hiring above the m-th best candidate: a generalization of records in permutations 

    Helmy, Ahmed Mohamed; Martínez Parra, Conrado; Panholzer, Alois (2011)
    External research report
    Open Access
    The hiring problem is a simple model of on-line decision- making under uncertainty. As in many other such models, the input is a sequence of instances and a decision must be taken for each instance depending on the subsequence ...
  • On deletions in open addressing hashing 

    Jiménez Gómez, Rosa María; Martínez Parra, Conrado (2011)
    External research report
    Open Access
    Deletions in open addressing tables have often been seen as problematic. The usual solution is to use a special mark ’deleted’ so that probe sequences continue past deleted slots, as if there was an element still sitting ...
  • On deletions in open addressing hashing 

    Jiménez Gómez, Rosa María; Martínez Parra, Conrado (Society for Industrial and Applied Mathematics (SIAM), 2018)
    Conference report
    Open Access
    Deletions in open addressing tables have often been seen as problematic. The usual solution is to use a special mark’deleted’ so that probe sequences continue past deleted slots, as if there was an element still sitting ...
  • On the average performance of fixed partial match queries in random relaxed K-d trees 

    Duch Brown, Amalia; Lau Laynes-Lozada, Gustavo Salvador; Martínez Parra, Conrado (2014)
    Conference report
    Restricted access - publisher's policy
    We obtain an explicit formula for the expected cost of a fixed partial match query in a random relaxed K-d tree, that is, the expected cost for a query of the form q = (q0 , q1 , . . . , qK-1 ) with 0 < s < K specified ...
  • On the average performance of orthogonal range search in multidimensional data structures 

    Duch Brown, Amalia; Martínez Parra, Conrado (2001-11)
    External research report
    Open Access
    In this work we present the average-case analysis of orthogonal range search for several multidimensional data structures. We first consider random relaxed K-d trees as a prototypical example and later extend our results ...
  • On the average size of the intersection of binary trees 

    Baeza Yates, Ricardo; Cases Muñoz, Rafel; Diaz Cort, Josep; Martínez Parra, Conrado (1989-01)
    External research report
    Open Access
    The average-case analysis of algorithms for binary search trees yields very different results from those obtained under the uniform distribution. The analysis itself is more complex and replaces algebraic equations by ...
  • On the competitiveness of the move-to-front rule 

    Roura Ferret, Salvador; Martínez Parra, Conrado (1996-11)
    External research report
    Open Access
    We consider the list access problem and show that one questionable assumption in the original cost model presented by Sleator and Tarjan (Amortized Efficiency of List Update and Paging Rules, CACM, 28(2):202-208, ...
  • On the cost of fixed partial match queries in K-d trees 

    Duch Brown, Amalia; Lau Laynes-Lozada, Gustavo Salvador; Martínez Parra, Conrado (2016-08-01)
    Article
    Open Access
    Partial match queries constitute the most basic type of associative queries in multidimensional data structures such as K-d trees or quadtrees. Given a query q=(q0,…,qK-1) where s of the coordinates are specified and K-s ...
  • On the number of descendants and ascendants in random search trees 

    Martínez Parra, Conrado; Prodinger, Helmut (1997-01)
    External research report
    Open Access
    We consider here the probabilistic analysis of the number of descendants and the number of ascendants of a given internal node in a random search tree. The performance of several important algorithms on search trees is ...
  • On the variance of quickselect 

    Daligault, Jean; Martínez Parra, Conrado (2005-10)
    External research report
    Open Access
    Quickselect with median-of-three is routinely used as the method of choice for selection of the mth element out of n in general-purpose libraries such as the C++ Standard Template Library. Its average behavior is fairly ...