s = append(s, w)
				parent[w.ID] = v.ID // keep overwriting this till it is visited.
			}
		}
	}
	return n
}

// compressOrig is the "simple" compress function from LT paper.
func compressOrig(v ID, ancestor, semi, label []ID) {
	if ancestor[ancestor[v]] != 0 {
		compressOrig(ancestor[v], ancestor, semi, label)
		if semi[label[ancestor[v]]] < semi[label[v]] {
			label[v] = label[ancestor[v]]
		}