出典:Wikipedia
出典:『Wikipedia』 (2011/02/12 10:46 UTC 版)
A shortest path tree, in graph theory, is a subgraph of a given (possibly weighted) graph constructed so that the distance between a selected root node and all other nodes is minimal. It is a tree because if there are two paths between the root node and some vertex v (i.e. a cycle), we can delete the last edge of the longer path without increasing the distance from the root node to any node in the subgraph.