On the cost of optimal alphabetic code trees with unequal letter costs
نویسندگان
چکیده
منابع مشابه
Optimal Alphabetic Trees
An algorithm of Knuth for finding an optimal binary tree is extended in several directions to solve related problems. The first case considered is restricting the depth of the tree by some predetermined integer K, and a Kn algorithm is given. Next, for trees of degree tr, rather than binary trees, Kn log tr and n log tr algorithms are found for the restricted and nonrestricted cases, respective...
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We give a new algorithm to construct optimal alphabetic ternary trees, where every internal node has at most three children. This algorithm generalizes the classic Hu-Tucker algorithm, though the overall computational complexity has yet to be determined.
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Several new observations which lead to new correctness proofs of two known algorithms (Hu-Tucker and Garsia-Wachs) for construction of optimal alphabetic trees are presented. A generalized version of the Garsia-Wachs algorithm is given. Proof of this generalized version works in a structured and illustrative way and clari es the usually poorly-understood behavior of both the Hu-Tucker and Garsi...
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In this paper we discuss a variation of the classical Huffman coding problem: finding optimal prefix-free codes for unequal letter costs. Our problem consists of finding a minimal cost prefix-free code in which the encoding alphabet consists of unequal cost (length) letters, with lengths α and β. The most efficient algorithm known previously required O(n) time to construct such a minimal-cost s...
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The Monge property emerges, sometimes quite mysteriously, in many optimization problems and usually leads to running time improvements of at least a linear factor. In this paper a novel application of memory reduced dynamic programming combined with a Monge property and the smawk algorithm is given for a variation of the Huuman coding problem: optimal preex-free codes for unequal letter costs. ...
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ژورنال
عنوان ژورنال: European Journal of Combinatorics
سال: 2008
ISSN: 0195-6698
DOI: 10.1016/j.ejc.2007.02.014