Browsing by Author "Martínez Parra, Conrado"

Analysis of an optimized search algorithm for skip lists
Martínez Parra, Conrado (199403)
External research report
Open AccessIt 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 medianofthree partition
Kirschenhofer, P; Martínez Parra, Conrado; Prodinger, H (199502)
External research report
Open AccessHoare'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 dualpivot Quicksort: A holistic analysis of Yaroslavskiy's partitioning scheme
Nebel, Markus E.; Wild, Sebastian; Martínez Parra, Conrado (201608)
Article
Open AccessThe new dualpivot Quicksort by Vladimir Yaroslavskiyused in Oracle's Java runtime library since version 7features 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 (200111)
External research report
Open AccessIn this paper we investigate the variants of the wellknown Hoare's Quickfind algorithm for the selection of the jth 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 alphaquantile"
Helmiy, Ahmed; Martínez Parra, Conrado; Panholzer, Alois (201211)
External research report
Open AccessWe study here the strategy hiring above the αquantile 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 (20030606)
External research report
Open AccessIn this report we combine two recent generation algorithms to obtain a new algorithm for the generation of unlabelled cycles. Sawada's algorithm lists all kary unlabelled cycles with fixed content, that is, the number ... 
A Topdown design of a parallel dictionary using skip lists
Gabarró Vallès, Joaquim; Martínez Parra, Conrado; Messeguer Peypoch, Xavier (199402)
External research report
Open AccessWe 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, 20130208)
Conference report / Conference lecture
Open AccessLa 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 LaynesLozada, Gustavo Salvador; Martínez Parra, Conrado (Schloss Dagstuhl  LeibnizZentrum für Informatik, 2018)
Conference report
Open AccessSeveral 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 (200306)
External research report
Open AccessThis 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 mth best candidate: a generalization of records in permutations
Helmy, Ahmed Mohamed; Martínez Parra, Conrado; Panholzer, Alois (2011)
External research report
Open AccessThe hiring problem is a simple model of online 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 AccessDeletions 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 AccessDeletions 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 Kd trees
Duch Brown, Amalia; Lau LaynesLozada, Gustavo Salvador; Martínez Parra, Conrado (2014)
Conference report
Restricted access  publisher's policyWe obtain an explicit formula for the expected cost of a fixed partial match query in a random relaxed Kd tree, that is, the expected cost for a query of the form q = (q0 , q1 , . . . , qK1 ) with 0 < s < K specified ... 
On the average performance of orthogonal range search in multidimensional data structures
Duch Brown, Amalia; Martínez Parra, Conrado (200111)
External research report
Open AccessIn this work we present the averagecase analysis of orthogonal range search for several multidimensional data structures. We first consider random relaxed Kd 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 (198901)
External research report
Open AccessThe averagecase 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 movetofront rule
Roura Ferret, Salvador; Martínez Parra, Conrado (199611)
External research report
Open AccessWe 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):202208, ... 
On the cost of fixed partial match queries in Kd trees
Duch Brown, Amalia; Lau LaynesLozada, Gustavo Salvador; Martínez Parra, Conrado (20160801)
Article
Open AccessPartial match queries constitute the most basic type of associative queries in multidimensional data structures such as Kd trees or quadtrees. Given a query q=(q0,…,qK1) where s of the coordinates are specified and Ks ... 
On the number of descendants and ascendants in random search trees
Martínez Parra, Conrado; Prodinger, Helmut (199701)
External research report
Open AccessWe 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 (200510)
External research report
Open AccessQuickselect with medianofthree is routinely used as the method of choice for selection of the mth element out of n in generalpurpose libraries such as the C++ Standard Template Library. Its average behavior is fairly ...