/// A single traversal step comprised of source and target nodes, and a
/// boolean flag indicating whether a cycle cut is present.
#[derive(Eq,PartialEq,Hash,Debug)]pubstructStep{pubsid:usize,
pubtid:usize,
pubcut:bool}implStep{pubfnnew(sid:usize, tid:usize, cut:bool)->Self{
Step { sid, tid, cut }}}