= Solution
Starting at `last.next`, visit each node once and stop when the traversal would return to its start. This helper is private so that callers do not receive writable nodes from the representation.
``
private def find(name: String): Node = {
if (last == null) return null
val first = last.next
var p = first
do {
if (p.name == name) return p
p = p.next
} while (p ne first)
null
}
``
\b[Null means no entry has that name.] The test `p ne first` compares <object identity>, not the equality of name or number fields. At each iteration all previously visited nodes failed the name test. The finite simple cycle guarantees that either a match is found or the traversal returns to `first` after exactly one turn. A singleton cycle is inspected exactly once. Stopping at null instead would fail to terminate on this representation.
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