pub fn count_root(&self) -> usize {
        self.adj
        .iter()
        .filter(|edge| edge.is_root())
        .count()
    }
/// Count how many root edges are contained
Count how many root edges are contained
Count how many root edges are contained
pub fn count_root(&self) -> usize {
        self.adj
        .iter()
        .filter(|edge| edge.is_root())
        .count()
    }
pub fn count_root ( & self ) -> usize { self . adj . iter ( ) . filter ( | edge | edge . is_root ( ) ) . count ( ) }
Count how many root edges are contained
Count how many root edges are contained
&self
&self