68 research outputs found

    Ordinal proportional cost sharing

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    We consider cost sharing problems with variable demands of heterogeneous goods. We study the compatibility of two axioms imposed on cost sharing methods: ordinality and average cost pricing for homogeneous (ACPH) goods. We generalize the ordinal proportional method (OPM) for the two-agent case, Sprumont [Journal of Economic Theory 81 (1998) 126162] to arbitrary number of agents

    An Efficient Dynamic Programming Algorithm for the Generalized LCS Problem with Multiple Substring Exclusion Constrains

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    In this paper, we consider a generalized longest common subsequence problem with multiple substring exclusion constrains. For the two input sequences XX and YY of lengths nn and mm, and a set of dd constrains P={P1,...,Pd}P=\{P_1,...,P_d\} of total length rr, the problem is to find a common subsequence ZZ of XX and YY excluding each of constrain string in PP as a substring and the length of ZZ is maximized. The problem was declared to be NP-hard\cite{1}, but we finally found that this is not true. A new dynamic programming solution for this problem is presented in this paper. The correctness of the new algorithm is proved. The time complexity of our algorithm is O(nmr)O(nmr).Comment: arXiv admin note: substantial text overlap with arXiv:1301.718

    A note on the largest number of red nodes in red-black trees

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    In this paper, we are interested in the number of red nodes in red-black trees. We first present an O(n2logn)O(n^2\log n) time dynamic programming solution for computing r(n)r(n), the largest number of red internal nodes in a red-black tree on nn keys. Then the algorithm is improved to some O(logn)O(\log n) time recursive and nonrecursive algorithms. Based on these improved algorithms we finally find a closed-form solution of r(n)r(n)

    Complete Solutions for a Combinatorial Puzzle in Linear Time

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    In this paper we study a single player game consisting of nn black checkers and mm white checkers, called shifting the checkers. We have proved that the minimum number of steps needed to play the game for general nn and mm is nm+n+mnm + n + m. We have also presented an optimal algorithm to generate an optimal move sequence of the game consisting of nn black checkers and mm white checkers, and finally, we present an explicit solution for the general game

    Rethinking the Value of Gazetteer in Chinese Named Entity Recognition

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    Gazetteer is widely used in Chinese named entity recognition (NER) to enhance span boundary detection and type classification. However, to further understand the generalizability and effectiveness of gazetteers, the NLP community still lacks a systematic analysis of the gazetteer-enhanced NER model. In this paper, we first re-examine the effectiveness several common practices of the gazetteer-enhanced NER models and carry out a series of detailed analysis to evaluate the relationship between the model performance and the gazetteer characteristics, which can guide us to build a more suitable gazetteer. The findings of this paper are as follows: (1) the gazetteer improves most of the situations that the traditional NER model datasets are difficult to learn. (2) the performance of model greatly benefits from the high-quality pre-trained lexeme embeddings. (3) a good gazetteer should cover more entities that can be matched in both the training set and testing set.Comment: Accepted by NLPCC 202
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