MAYBE

We are left with following problem, upon which TcT provides the
certificate MAYBE.

Strict Trs:
  { empty(nil()) -> true()
  , empty(cons(x, l)) -> false()
  , head(cons(x, l)) -> x
  , tail(nil()) -> nil()
  , tail(cons(x, l)) -> l
  , rev(nil()) -> nil()
  , rev(cons(x, l)) -> cons(rev1(x, l), rev2(x, l))
  , rev2(x, nil()) -> nil()
  , rev2(x, cons(y, l)) -> rev(cons(x, rev2(y, l)))
  , last(x, l) -> if(empty(l), x, l)
  , if(true(), x, l) -> x
  , if(false(), x, l) -> last(head(l), tail(l)) }
Obligation:
  innermost runtime complexity
Answer:
  MAYBE

The input cannot be shown compatible

Arrrr..