翻訳と辞書 Words near each other ・ List of Ōban Star-Racers episodes ・ List of Ōkami Kakushi episodes ・ List of ŠK Slovan Bratislava award winners and top goal scorers ・ List of ŠK Slovan Bratislava managers ・ List of ŠK Slovan Bratislava players ・ List of ŠK Slovan Bratislava players in the Czechoslovak or Slovak national team ・ List of Škoda Auto engines ・ List of Škoda Transportation products ・ List of β-lactam antibiotics ・ List poisoning ・ List price ・ List Project ・ List ranking ・ List scheduling ・ List song ・ List update problem ・ List Visual Arts Center ・ List winners of Czech Republic championship in English draughts ・ List X site ・ LISTA ・ Lista ・ Lista (disambiguation) ・ Lista (Madrid Metro) ・ Lista (moth) ・ Lista Air Station ・ Lista carniola ・ Lista civica ・ Lista de Espera ・ Lista ficki ・ Lista haraldusalis Dictionary Lists mini英和辞書 mini和英辞書 Webster 1913 Latin-English FOLDOC Wikipedia English ウィキペディア

翻訳と辞書　辞書検索 [ 開発暫定版 ] スポンサード リンク List update problem ： ウィキペディア英語版 List update problem The List Update or the List Access problem is a simple model used in the study of competitive analysis of online algorithms. Given a set of items in a list where the cost of accessing an item is proportional to its distance from the head of the list, e.g. a Linked List, and a request sequence of accesses, the problem is to come up with a strategy of reordering the list so that the total cost of accesses is minimized. The reordering can be done at any time but incurs a cost. The standard model includes two reordering actions: * A free transposition of the item being accessed anywhere ahead of its current position; * A paid transposition of a unit cost for exchanging any two items in the list. Performance of algorithms depend on the construction of request sequences by adversaries under various Adversary models An online algorithm for this problem has to reorder the elements and serve requests based only on the knowledge of previously requested items and hence its strategy may not have the optimum cost as compared to an offline algorithm that gets to see the entire request sequence and devise a complete strategy before serving the first request. ==Adversary Models== An adversary is an entity that gets to choose the request sequence $\backslash sigma$ for an algorithm ''ALG''. Depending of whether $\backslash sigma$ can be changed based on the strategy of ''ALG'', adversaries are given various powers, and the performance of ''ALG'' is measured against these adversaries. An oblivious adversary has to construct the entire request sequence $\backslash sigma$ before running ''ALG'', and pays the optimal offline price, $OPT(\backslash sigma)$ which is compared against $ALG(\backslash sigma)$ An adaptive online adversary gets to make the next request based on the previous results of the online algorithm, but pays for the request optimally and online. An adaptive offline adversary gets to make the next request based on the previous results of the online algorithm, but pays the optimal offline cost. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「List update problem」の詳細全文を読む スポンサード リンク 翻訳と辞書 : 翻訳のためのインターネットリソース Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.