gets the head of this arc the node where this arc ends . concode_field_sep Node<Label> head concode_elem_sep float cost concode_elem_sep Node<Label> tail concode_elem_sep Label label concode_field_sep Node<Label> getTail concode_elem_sep Label getLabel concode_elem_sep String toString concode_elem_sep float getCost
Node < Label > function ( ) { return head ; }