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- Johannes Fischer, Volker Heun
- SIAM J. Comput.
- 2011

Given a static array of n totally ordered object, the range minimum query problem is to build an additional data structure that allows to answer subsequent on-line queries of the form " what is the position of a minimum element in the sub-array ranging from i to j? " efficiently. We focus on two settings, where (1) the input array is available at query… (More)

- Johannes Fischer, Volker Heun
- ESCAPE
- 2007

The Range-Minimum-Query-Problem is to preprocess an array of length n in O(n) time such that all subsequent queries asking for the position of a minimal element between two specified indices can be obtained in constant time. This problem was first solved by Berkman and Vishkin [1], and Sadakane [2] gave the first succinct data structure that uses 4n + o(n)… (More)

- Johannes Fischer, Veli Mäkinen, Gonzalo Navarro
- Theor. Comput. Sci.
- 2009

Suffix trees are among the most important data structures in stringology, with a number of applications in flourishing areas like bioinformatics. Their main problem is space usage, which has triggered much research striving for compressed representations that are still functional. A smaller suffix tree representation could fit in a faster memory,… (More)

- Johannes Fischer
- Theor. Comput. Sci.
- 2011

Let A be a static array storing n elements from a totally ordered set. We present a data structure of optimal size at most n log 2 (3 + 2 √ 2) + o(n) bits that allows us to answer the following queries on A in constant time, without accessing A: (1) previous smaller value queries, where given an index i, we wish to find the first index to the left of i… (More)

- Johannes Fischer
- WADS
- 2011

We show how to modify the linear-time construction algorithm for suffix arrays based on induced sorting (Nong et al., DCC'09) such that it computes the array of longest common prefixes (LCP-array) as well. Practical tests show that this outperforms recent LCP-array construction algorithms (Gog and Ohlebusch, ALENEX'11).

- Johannes Fischer, Volker Heun, Stefan Kramer
- PKDD
- 2006

We propose a new algorithmic framework that solves frequency related data mining queries on databases of strings in optimal time, i.e., in time linear in the input and the output size. The additional space is linear in the input size. Our framework can be used to mine frequent strings, emerging strings and strings that pass other statistical tests, e.g.,… (More)

- Johannes Fischer, Pawel Gawrychowski
- CPM
- 2015

It is widely assumed that O(m + lg σ) is the best one can do for finding a pattern of length m in a compacted trie storing strings over an alphabet of size σ, if one insists on linear-size data structures and deterministic worst-case running times [Cole et al., ICALP'06]. In this article, we first show that a rather straightforward combination of well-known… (More)

- Sabine Spiegl-Kreinecker, Christine Pirker, +8 authors Walter Berger
- Neuro-oncology
- 2010

O(6)-Methylguanine DNA methyltransferase (MGMT) is implicated as a major predictive factor for treatment response to alkylating agents including temozolomide (TMZ) of glioblastoma multiforme (GBM) patients. However, whether the MGMT status in GBM patients should be detected at the level of promoter methylation or protein expression is still a matter of… (More)

- Sabine Spiegl-Kreinecker, Johanna Buchroithner, +6 authors Walter Berger
- Journal of Neuro-Oncology
- 2002

The poor prognosis of glioma patients is partly based on the minor success obtained from chemotherapeutic treatments. Resistance mechanisms at the tumor cell level may be, in addition to the blood–brain barrier, involved in the intrinsic chemo-insensitivity of brain tumors. We investigated the expression of the drug-transporter proteins P-glycoprotein… (More)

- Johannes Fischer, Volker Heun
- CPM
- 2006

The Range-Minimum-Query-Problem is to preprocess an array such that the position of the minimum element between two specified indices can be obtained efficiently. We present a direct algorithm for the general RMQ-problem with linear preprocessing time and constant query time, without making use of any dynamic data structure. It consumes less than half of… (More)