Search Results

Documents authored by Orlandi, Alessio


Document
Education
Turing Arena Light: Enhancing Programming Education Through Competitive Environments

Authors: Giorgio Audrito, Luigi Laura, Alessio Orlandi, Dario Ostuni, Romeo Rizzi, and Luca Versari

Published in: OASIcs, Volume 132, From Strings to Graphs, and Back Again: A Festschrift for Roberto Grossi's 60th Birthday (2025)


Abstract
Turing Arena light, the spiritual successor of Turing Arena, is a contest management system that is designed to be more geared towards the needs of classroom teaching, rather than competitive programming contests. It strives to be as simple as possible, while being very flexible and extensible. The fundamental idea behind Turing Arena light is to have two programs that talk to each other through the standard input and output channels. One of the two programs is the problem manager, which is a program that interacts with a solution to give it the input and evaluate its output, and eventually give a verdict. The other program is the solution, which is the program written by the contestant that is meant to solve the problem. In this paper we describe the architecture and the design of Turing Arena light.

Cite as

Giorgio Audrito, Luigi Laura, Alessio Orlandi, Dario Ostuni, Romeo Rizzi, and Luca Versari. Turing Arena Light: Enhancing Programming Education Through Competitive Environments. In From Strings to Graphs, and Back Again: A Festschrift for Roberto Grossi's 60th Birthday. Open Access Series in Informatics (OASIcs), Volume 132, pp. 11:1-11:14, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)


Copy BibTex To Clipboard

@InProceedings{audrito_et_al:OASIcs.Grossi.11,
  author =	{Audrito, Giorgio and Laura, Luigi and Orlandi, Alessio and Ostuni, Dario and Rizzi, Romeo and Versari, Luca},
  title =	{{Turing Arena Light: Enhancing Programming Education Through Competitive Environments}},
  booktitle =	{From Strings to Graphs, and Back Again: A Festschrift for Roberto Grossi's 60th Birthday},
  pages =	{11:1--11:14},
  series =	{Open Access Series in Informatics (OASIcs)},
  ISBN =	{978-3-95977-391-1},
  ISSN =	{2190-6807},
  year =	{2025},
  volume =	{132},
  editor =	{Conte, Alessio and Marino, Andrea and Rosone, Giovanna and Vitter, Jeffrey Scott},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.Grossi.11},
  URN =		{urn:nbn:de:0030-drops-238108},
  doi =		{10.4230/OASIcs.Grossi.11},
  annote =	{Keywords: Competitive Programming, Contest Management Systems, Online Judges}
}
Document
More Haste, Less Waste: Lowering the Redundancy in Fully Indexable Dictionaries

Authors: Roberto Grossi, Alessio Orlandi, Rajeev Raman, and S. Srinivasa Rao

Published in: LIPIcs, Volume 3, 26th International Symposium on Theoretical Aspects of Computer Science (2009)


Abstract
We consider the problem of representing, in a compressed format, a bit-vector~$S$ of $m$ bits with $n$ $\mathbf{1}$s, supporting the following operations, where $b \in \{ \mathbf{0}, \mathbf{1} \}$: \begin{itemize} \item $\mathtt{rank}_b(S,i)$ returns the number of occurrences of bit $b$ in the prefix $S\left[1..i\right]$; \item $\mathtt{select}_b(S,i)$ returns the position of the $i$th occurrence of bit $b$ in $S$. \end{itemize} Such a data structure is called \emph{fully indexable dictionary (\textsc{fid})} [Raman, Raman, and Rao, 2007], and is at least as powerful as predecessor data structures. Viewing $S$ as a set $X = \{ x_1, x_2, \ldots, x_n \}$ of $n$ distinct integers drawn from a universe $[m] = \{1, \ldots, m\}$, the predecessor of integer $y \in [m]$ in $X$ is given by $\ensuremath{\mathtt{select}^{}_1}(S, \ensuremath{\mathtt{rank}_1}(S,y-1))$. {\textsc{fid}}s have many applications in succinct and compressed data structures, as they are often involved in the construction of succinct representation for a variety of abstract data types. Our focus is on space-efficient {\textsc{fid}}s on the \textsc{ram} model with word size $\Theta(\lg m)$ and constant time for all operations, so that the time cost is independent of the input size. Given the bitstring $S$ to be encoded, having length $m$ and containing $n$ ones, the minimal amount of information that needs to be stored is $B(n,m) = \lceil \log {{m}\choose{n}} \rceil$. The state of the art in building a \textsc{fid}\ for~$S$ is given in~\mbox{}[P\v{a}tra\c{s}cu, 2008] using $B(m,n)+O( m / ( (\log m/ t) ^t) ) + O(m^{3/4}) $ bits, to support the operations in $O(t)$ time. Here, we propose a parametric data structure exhibiting a time/space trade-off such that, for any real constants $0 < \delta \leq 1/2$, $0 < \varepsilon \leq 1$, and integer $s > 0$, it uses \[ B(n,m) + O\left(n^{1+\delta} + n \left(\frac{m}{n^s}\right)^\varepsilon\right) \] bits and performs all the operations in time $O(s\delta^{-1} + \varepsilon^{-1})$. The improvement is twofold: our redundancy can be lowered parametrically and, fixing $s = O(1)$, we get a constant-time \textsc{fid}\ whose space is $B(n,m) + O(m^\varepsilon/\mathrm{poly}(n))$ bits, for sufficiently large $m$. This is a significant improvement compared to the previous bounds for the general case.

Cite as

Roberto Grossi, Alessio Orlandi, Rajeev Raman, and S. Srinivasa Rao. More Haste, Less Waste: Lowering the Redundancy in Fully Indexable Dictionaries. In 26th International Symposium on Theoretical Aspects of Computer Science. Leibniz International Proceedings in Informatics (LIPIcs), Volume 3, pp. 517-528, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2009)


Copy BibTex To Clipboard

@InProceedings{grossi_et_al:LIPIcs.STACS.2009.1847,
  author =	{Grossi, Roberto and Orlandi, Alessio and Raman, Rajeev and Rao, S. Srinivasa},
  title =	{{More Haste, Less Waste: Lowering the Redundancy in Fully Indexable Dictionaries}},
  booktitle =	{26th International Symposium on Theoretical Aspects of Computer Science},
  pages =	{517--528},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-09-5},
  ISSN =	{1868-8969},
  year =	{2009},
  volume =	{3},
  editor =	{Albers, Susanne and Marion, Jean-Yves},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.STACS.2009.1847},
  URN =		{urn:nbn:de:0030-drops-18470},
  doi =		{10.4230/LIPIcs.STACS.2009.1847},
  annote =	{Keywords: }
}
Any Issues?
X

Feedback on the Current Page

CAPTCHA

Thanks for your feedback!

Feedback submitted to Dagstuhl Publishing

Could not send message

Please try again later or send an E-mail