### 抜粋

Given an undirected and edge-weighted graph G together with a set of ordered vertex-pairs, called st-pairs, we consider the problems of finding an orientation of all edges in G: min-sum orientation is to minimize the sum of the shortest directed distances between all st-pairs; and min-max orientation is to minimize the maximum shortest directed distance among all st-pairs. In this paper, we first show that both problems are strongly NP-hard for planar graphs even if all edge-weights are identical, and that both problems can be solved in polynomial time for cycles. We then consider the problems restricted to cacti, which form a graph class that contains trees and cycles but is a subclass of planar graphs. Then, min-sum orientation is solvable in polynomial time, whereas min-max orientation remains NP-hard even for two st-pairs. However, based on LP-relaxation, we present a polynomial-time 2-approximation algorithm for min-max orientation. Finally, we give a fully polynomial-time approximation scheme (FPTAS) for min-max orientation on cacti if the number of st-pairs is a fixed constant.

元の言語 | English |
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ホスト出版物のタイトル | Algorithms and Computation - 20th International Symposium, ISAAC 2009, Proceedings |

ページ | 403-412 |

ページ数 | 10 |

DOI | |

出版物ステータス | Published - 2009 12 1 |

イベント | 20th International Symposium on Algorithms and Computation, ISAAC 2009 - Honolulu, HI, United States 継続期間: 2009 12 16 → 2009 12 18 |

### 出版物シリーズ

名前 | Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) |
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巻 | 5878 LNCS |

ISSN（印刷物） | 0302-9743 |

ISSN（電子版） | 1611-3349 |

### Other

Other | 20th International Symposium on Algorithms and Computation, ISAAC 2009 |
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国 | United States |

市 | Honolulu, HI |

期間 | 09/12/16 → 09/12/18 |

### ASJC Scopus subject areas

- Theoretical Computer Science
- Computer Science(all)

## フィンガープリント Route-enabling graph orientation problems' の研究トピックを掘り下げます。これらはともに一意のフィンガープリントを構成します。

## これを引用

*Algorithms and Computation - 20th International Symposium, ISAAC 2009, Proceedings*(pp. 403-412). (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics); 巻数 5878 LNCS). https://doi.org/10.1007/978-3-642-10631-6_42