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出 版 物:《SIAM Journal on Computing》
年 卷 期:1977年第6卷第3期
页 面:563-581页
学科分类:07[理学] 070104[理学-应用数学] 0701[理学-数学]
主 题:traveling salesman problem approximation algorithm -optimal minimal spanning tree triangle inequality
摘 要:Several polynomial time algorithms finding “good, but not necessarily optimal, tours for the traveling salesman problem are considered. We measure the closeness of a tour by the ratio of the obtained tour length to the minimal tour length. For the nearest neighbor method, we show the ratio is bounded above by a logarithmic function of the number of nodes. We also provide a logarithmic lower bound on the worst case. A class of approximation methods we call insertion methods are studied, and these are also shown to have a logarithmic upper bound. For two specific insertion methods, which we call nearest insertion and cheapest insertion, the ratio is shown to have a constant upper bound of 2, and examples are provided that come arbitrarily close to this upper bound. It is also shown that for any n8 role=presentationn≧8span style=display: inline-block; overflow: hidden; vertical-align: -0.265em