MAYBE
Time: 0.009434
TRS:
 {   g(empty(), d) -> d,
  g(cons(x, k), d) -> g(k, cons(x, d)),
     f(a, empty()) -> g(a, empty()),
  f(a, cons(x, k)) -> f(cons(x, a), k)}
 DP:
  DP:
   {g#(cons(x, k), d) -> g#(k, cons(x, d)),
       f#(a, empty()) -> g#(a, empty()),
    f#(a, cons(x, k)) -> f#(cons(x, a), k)}
  TRS:
  {   g(empty(), d) -> d,
   g(cons(x, k), d) -> g(k, cons(x, d)),
      f(a, empty()) -> g(a, empty()),
   f(a, cons(x, k)) -> f(cons(x, a), k)}
  UR:
   {}
   EDG:
    {(g#(cons(x, k), d) -> g#(k, cons(x, d)), g#(cons(x, k), d) -> g#(k, cons(x, d)))
     (f#(a, empty()) -> g#(a, empty()), g#(cons(x, k), d) -> g#(k, cons(x, d)))
     (f#(a, cons(x, k)) -> f#(cons(x, a), k), f#(a, empty()) -> g#(a, empty()))
     (f#(a, cons(x, k)) -> f#(cons(x, a), k), f#(a, cons(x, k)) -> f#(cons(x, a), k))}
    STATUS:
     arrows: 0.555556
     SCCS (2):
      Scc:
       {f#(a, cons(x, k)) -> f#(cons(x, a), k)}
      Scc:
       {g#(cons(x, k), d) -> g#(k, cons(x, d))}
      
      SCC (1):
       Strict:
        {f#(a, cons(x, k)) -> f#(cons(x, a), k)}
       Weak:
       {   g(empty(), d) -> d,
        g(cons(x, k), d) -> g(k, cons(x, d)),
           f(a, empty()) -> g(a, empty()),
        f(a, cons(x, k)) -> f(cons(x, a), k)}
       Open
      
      SCC (1):
       Strict:
        {g#(cons(x, k), d) -> g#(k, cons(x, d))}
       Weak:
       {   g(empty(), d) -> d,
        g(cons(x, k), d) -> g(k, cons(x, d)),
           f(a, empty()) -> g(a, empty()),
        f(a, cons(x, k)) -> f(cons(x, a), k)}
       Open