WORST_CASE(?,O(n^2))

Solution:
---------

  0 :: [] -(0)-> Nat(7, 2)
  checkF :: [Q(0, 1)] -(3)-> Q(0, 0)
  cons :: [Nat(0, 0) x L(1, 0)] -(1)-> L(1, 0)
  cons :: [Nat(0, 0) x L(0, 0)] -(0)-> L(0, 0)
  empty :: [] -(1)-> Q(0, 0)
  enq :: [Nat(7, 2)] -(2)-> Q(0, 0)
  errorHead :: [] -(0)-> Nat(0, 0)
  errorTail :: [] -(0)-> Q(0, 0)
  head :: [Q(0, 0)] -(1)-> Nat(0, 0)
  nil :: [] -(0)-> L(1, 0)
  nil :: [] -(0)-> L(0, 0)
  queue :: [L(0, 0) x L(1, 0)] -(0)-> Q(0, 1)
  queue :: [L(0, 0) x L(0, 0)] -(0)-> Q(0, 0)
  rev :: [L(1, 0)] -(2)-> L(0, 0)
  rev' :: [L(1, 0) x L(0, 0)] -(1)-> L(0, 0)
  s :: [Nat(9, 2)] -(7)-> Nat(7, 2)
  snoc :: [Q(0, 1) x Nat(0, 0)] -(5)-> Q(0, 0)
  tail :: [Q(0, 1)] -(4)-> Q(0, 0)


Cost Free Signatures:
---------------------

  0 :: [] -(0)-> Nat_cf(2, 0)
  checkF :: [Q_cf(1, 1)] -(1)-> Q_cf(1, 1)
  cons :: [Nat_cf(0, 0) x L_cf(0, 0)] -(0)-> L_cf(0, 0)
  cons :: [Nat_cf(0, 0) x L_cf(1, 0)] -(1)-> L_cf(1, 0)
  empty :: [] -(1)-> Q_cf(1, 1)
  enq :: [Nat_cf(2, 0)] -(1)-> Q_cf(1, 1)
  nil :: [] -(0)-> L_cf(0, 0)
  nil :: [] -(0)-> L_cf(1, 1)
  nil :: [] -(0)-> L_cf(1, 0)
  queue :: [L_cf(1, 0) x L_cf(1, 0)] -(0)-> Q_cf(1, 1)
  rev :: [L_cf(1, 0)] -(1)-> L_cf(1, 0)
  rev' :: [L_cf(0, 0) x L_cf(0, 0)] -(0)-> L_cf(0, 0)
  rev' :: [L_cf(1, 0) x L_cf(1, 0)] -(1)-> L_cf(1, 0)
  s :: [Nat_cf(2, 0)] -(2)-> Nat_cf(2, 0)
  snoc :: [Q_cf(1, 1) x Nat_cf(0, 0)] -(2)-> Q_cf(1, 1)