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arXiv 1608.04769cs.DS
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用于单源距离的紧凑快速灵敏度预言机

Compact and Fast Sensitivity Oracles for Single-Source Distances

Davide Bilò, Luciano Gualà, Stefano Leucci, Guido Proietti

摘要:

令$s$表示具有$n$顶点和$m$边的非负实加权无向图$G$的一个可区别的源顶点。在本文中,我们提出了两个有效的\emph{single-source approximate-distance sensitivity oracles},即\emph{compact}数据结构,能够\emph{quickly}报告一个近似(乘拉伸因子)的距离从$s$到$G$的任何节点的$G$中的任何边缘的故障。更确切地说,我们首先提出了一个灵敏度预言的大小$O(n)$,这是能够报告2-近似距离源在$O(1)$的时间。然后,我们进一步发展我们的建设,为任何$0<ε<1$,另一个灵敏度oracle的大小$O\left(n\cdot \frac{1}ε \log \frac{1}ε\right)$,并能够报告一个$(1+ε)$ -近似距离$s$任何顶点的$G$在$O\left(\log n\cdot \frac{1}ε \log \frac{1}ε\right)$时间。因此,就大小和延伸而言,后一个预言机本质上是最优的,并且它只要求对数查询时间。最后,我们的结果补充了一个空间下界的相关类的单源\emph{additively-stretched}灵敏度预言机,这是有助于实现的难度设计紧凑的这类预言机。

英文摘要:

Let $s$ denote a distinguished source vertex of a non-negatively real weighted and undirected graph $G$ with $n$ vertices and $m$ edges. In this paper we present two efficient \emph{single-source approximate-distance sensitivity oracles}, namely \emph{compact} data structures which are able to \emph{quickly} report an approximate (by a multiplicative stretch factor) distance from $s$ to any node of $G$ following the failure of any edge in $G$. More precisely, we first present a sensitivity oracle of size $O(n)$ which is able to report 2-approximate distances from the source in $O(1)$ time. Then, we further develop our construction by building, for any $0<ε<1$, another sensitivity oracle having size $O\left(n\cdot \frac{1}ε \log \frac{1}ε\right)$, and which is able to report a $(1+ε)$-approximate distance from $s$ to any vertex of $G$ in $O\left(\log n\cdot \frac{1}ε \log \frac{1}ε\right)$ time. Thus, this latter oracle is essentially optimal as far as size and stretch are concerned, and it only asks for a logarithmic query time. Finally, our results are complemented with a space lower bound for the related class of single-source \emph{additively-stretched} sensitivity oracles, which is helpful to realize the hardness of designing compact oracles of this type.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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