Method partial_cmp

publication/code/chapter09/dijkstra.rs:33–35

(&self, other: &Self)

impl<V> PartialOrd for Visited<V> {
    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
        Some(self.cmp(other))
    }
}

impl<V> Eq for Visited<V> {}