abstract:Given a directed graph G = (V, E), a path cover is a set of directed paths such that every vertex v ∈ V belongs to at least one path. Note that a path cover may include paths of length 0 (a single vertex).
Visitors enter the park via a broad, pebbled avenue lined with twin rows of gingko trees, considered by many to be one of the most beautiful sights in the capital, especially in the autumn when golden leaves cover the path and in spring when the trees turn a fresh green.