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Efficient validation and construction of border arrays and validation of string matching automata

Jean-Pierre Duval, Thierry Lecroq, Arnaud Lefebvre (2009)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

We present an on-line linear time and space algorithm to check if an integer array f is the border array of at least one string w built on a bounded or unbounded size alphabet Σ . First of all, we show a bijection between the border array of a string w and the skeleton of the DFA recognizing Σ * w , called a string matching automaton (SMA). Different strings can have the same border array but the originality of the presented method is that the correspondence between a border array and a skeleton of SMA...

Efficient validation and construction of border arrays and validation of string matching automata

Jean-Pierre Duval, Thierry Lecroq, Arnaud Lefebvre (2008)

RAIRO - Theoretical Informatics and Applications

We present an on-line linear time and space algorithm to check if an integer array f is the border array of at least one string w built on a bounded or unbounded size alphabet Σ. First of all, we show a bijection between the border array of a string w and the skeleton of the DFA recognizing Σ*ω, called a string matching automaton (SMA). Different strings can have the same border array but the originality of the presented method is that the correspondence between a border array and a...

Measuring the problem-relevant information in input

Stefan Dobrev, Rastislav Královič, Dana Pardubská (2009)

RAIRO - Theoretical Informatics and Applications

We propose a new way of characterizing the complexity of online problems. Instead of measuring the degradation of the output quality caused by the ignorance of the future we choose to quantify the amount of additional global information needed for an online algorithm to solve the problem optimally. In our model, the algorithm cooperates with an oracle that can see the whole input. We define the advice complexity of the problem to be the minimal number of bits (normalized per input request, and...

Near-minimal spanning trees : a scaling exponent in probability models

David J. Aldous, Charles Bordenave, Marc Lelarge (2008)

Annales de l'I.H.P. Probabilités et statistiques

We study the relation between the minimal spanning tree (MST) on many random points and the “near-minimal” tree which is optimal subject to the constraint that a proportion δ of its edges must be different from those of the MST. Heuristics suggest that, regardless of details of the probability model, the ratio of lengths should scale as 1+Θ(δ2). We prove this scaling result in the model of the lattice with random edge-lengths and in the euclidean model.

On the Horton-Strahler Number for Combinatorial Tries

Markus E. Nebel (2010)

RAIRO - Theoretical Informatics and Applications

In this paper we investigate the average Horton-Strahler number of all possible tree-structures of binary tries. For that purpose we consider a generalization of extended binary trees where leaves are distinguished in order to represent the location of keys within a corresponding trie. Assuming a uniform distribution for those trees we prove that the expected Horton-Strahler number of a tree with α internal nodes and β leaves that correspond to a key is asymptotically given by 4 2 β - α log ( α ) ( 2 β - 1 ) ( α + 1 ) ( α + 2 ) 2 α + 1 α - 1 8 π α 3 / 2 log ( 2 ) ( β - 1 ) β 2 β β 2 provided that α...

On the power of randomization for job shop scheduling with k -units length tasks

Tobias Mömke (2009)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

In the job shop scheduling problem k -units- J m , there are m machines and each machine has an integer processing time of at most k time units. Each job consists of a permutation of m tasks corresponding to all machines and thus all jobs have an identical dilation D . The contribution of this paper are the following results; (i) for d = o ( D ) jobs and every fixed k , the makespan of an optimal schedule is at most D + o ( D ) , which extends the result of [3] for k = 1 ; (ii) a randomized on-line approximation algorithm for k -units-...

On the power of randomization for job shop scheduling with k-units length tasks

Tobias Mömke (2008)

RAIRO - Theoretical Informatics and Applications

In the job shop scheduling problem k-units-Jm, there are m machines and each machine has an integer processing time of at most k time units. Each job consists of a permutation of m tasks corresponding to all machines and thus all jobs have an identical dilation D. The contribution of this paper are the following results; (i) for d = o ( D ) jobs and every fixed k, the makespan of an optimal schedule is at most D+ o(D), which extends the result of [3] for k=1; (ii) a randomized on-line approximation...

On the reduction of a random basis

Ali Akhavi, Jean-François Marckert, Alain Rouault (2009)

ESAIM: Probability and Statistics

For p ≤ n, let b1(n),...,bp(n) be independent random vectors in n with the same distribution invariant by rotation and without mass at the origin. Almost surely these vectors form a basis for the Euclidean lattice they generate. The topic of this paper is the property of reduction of this random basis in the sense of Lenstra-Lenstra-Lovász (LLL). If b ^ 1 ( n ) , ... , b ^ p ( n ) is the basis obtained from b1(n),...,bp(n) by Gram-Schmidt orthogonalization, the quality of the reduction depends upon the sequence of ratios...

On the stack-size of general tries

Jérémie Bourdon, Markus Nebel, Brigitte Vallée (2001)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

Digital trees or tries are a general purpose flexible data structure that implements dictionaries built on words. The present paper is focussed on the average-case analysis of an important parameter of this tree-structure, i.e., the stack-size. The stack-size of a tree is the memory needed by a storage-optimal preorder traversal. The analysis is carried out under a general model in which words are produced by a source (in the information-theoretic sense) that emits symbols. Under some natural assumptions...

On the Stack-Size of General Tries

Jérémie Bourdon, Markus Nebel, Brigitte Vallée (2010)

RAIRO - Theoretical Informatics and Applications

Digital trees or tries are a general purpose flexible data structure that implements dictionaries built on words. The present paper is focussed on the average-case analysis of an important parameter of this tree-structure, i.e., the stack-size. The stack-size of a tree is the memory needed by a storage-optimal preorder traversal. The analysis is carried out under a general model in which words are produced by a source (in the information-theoretic sense) that emits symbols. Under some natural...

Signed bits and fast exponentiation

Wieb Bosma (2001)

Journal de théorie des nombres de Bordeaux

An exact analysis is given of the benefits of using the non-adjacent form representation for integers (rather than the binary representation), when computing powers of elements in a group in which inverting is easy. By counting the number of multiplications for a random exponent requiring a given number of bits in its binary representation, we arrive at a precise version of the known asymptotic result that on average one in three signed bits in the non-adjacent form is non-zero. This shows that...

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