Theoretical Computer Science ( IF 1.1 ) Pub Date : 2021-01-07 , DOI: 10.1016/j.tcs.2021.01.006 Guozhen Rong , Wenjun Li , Yongjie Yang , Jianxin Wang
A hidden graph is a graph whose edge set is hidden. A distance oracle of a graph G is a black-box that receives two vertices of G and outputs the distance between the two vertices. Given a hidden graph, the reconstruction problem aims to identify the edges of the hidden graph by accessing a distance oracle, and the verification problem aims to check whether the hidden graph is equal to another given graph (not hidden).
If the hidden graph G is a connected chordal graph, a Las Vegas reconstruction algorithm using distance queries is known, where Δ is the maximum degree of G and n is the number of vertices of G. Improving upon this result, we present a reconstruction algorithm using only distance queries. As a byproduct, we obtain a deterministic algorithm for the verification of chordal graphs with distance queries. Additionally, we derive a deterministic algorithm of reconstructing connected interval graphs using only distance queries, and prove that reconstructing or verifying a connected interval graph needs distance queries, which implies that this algorithm is the best possible in terms of the number of distance queries needed.
中文翻译:
带距离预言的和弦图的重建和验证
隐藏图是其边集被隐藏的图。图G的距离预言是一个黑盒,它接收G的两个顶点并输出两个顶点之间的距离。给定一个隐藏图,重建问题旨在通过访问距离预言来识别隐藏图的边缘,而验证问题旨在检查该隐藏图是否等于另一个给定图(未隐藏)。
如果隐藏图G是连通弦图,则使用距离查询是已知的,其中Δ是最大程度ģ和Ñ是顶点的数量ģ。为了改善这个结果,我们提出了一种仅使用距离查询。作为副产品,我们获得了确定性算法,用于验证弦图距离查询。此外,我们推导了一种确定性算法,该算法仅使用 距离查询,并证明需要重建或验证连接的间隔图 距离查询,这意味着就所需的距离查询而言,该算法是最好的。