5 research outputs found
Locating regions in a sequence under density constraints
Several biological problems require the identification of regions in a
sequence where some feature occurs within a target density range: examples
including the location of GC-rich regions, identification of CpG islands, and
sequence matching. Mathematically, this corresponds to searching a string of 0s
and 1s for a substring whose relative proportion of 1s lies between given lower
and upper bounds. We consider the algorithmic problem of locating the longest
such substring, as well as other related problems (such as finding the shortest
substring or a maximal set of disjoint substrings). For locating the longest
such substring, we develop an algorithm that runs in O(n) time, improving upon
the previous best-known O(n log n) result. For the related problems we develop
O(n log log n) algorithms, again improving upon the best-known O(n log n)
results. Practical testing verifies that our new algorithms enjoy significantly
smaller time and memory footprints, and can process sequences that are orders
of magnitude longer as a result.Comment: 17 pages, 8 figures; v2: minor revisions, additional explanations; to
appear in SIAM Journal on Computin
Creating informatics olympiad tasks: Exploring the black art
Each year a wealth of informatics olympiads are held worldwide at national, regional and international levels, all of which require engaging and challenging tasks that have not been seen before. Nevertheless, creating high quality tasks can be a difficult and time-consuming process. In this paper we explore some of the different techniques that problem setters can use to find new ideas for tasks and refine these ideas into problems suitable for an informatics olympiad. These techniques are illustrated through concrete examples from a variety of contests
France-IOI : l'apprentissage de l'algorithmique pour tous
Depuis 1996, la France participe aux Olympiades Internationales d'Informatique. L'association France-IOI, en charge de la préparation de l'équipe de France, a formé à la programmation et à l'algorithmique plusieurs centaines de collégiens et lycéens par l'intermédiaire de son site internet. Dans cet article, nous présenterons les Olympiades d'Informatique ainsi que l'association France-IOI et nous expliquerons les méthodes mises en œuvre pour enseigner à des jeunes la programmation et l'algorithmique de manière ludique
Coding Tutorials for any Programming Language or Interactive Tutorials for C and Arduino
International audienc
Get involved! The IOI workshop 2010, its goals and results
In May 2010, the third IOI workshop took place in Schloss Dagstuhl, Germany. It was motivated by the discussions held at and after the panel session of 2009's IOI conference in Plovdiv. There, discussions focussed on communication and collaboration among the IOI community, as well as communication of the IOI competition to outsiders. At the workshop, members of the IOI community met to develop a first version of an IOI Wiki as a tool for communication and collaboration, and devised suggestions on how to visualize IOI-style contests to make them more accessible to the outside world