We are left with following problem, upon which TcT provides the
certificate YES(?,O(n^1)).

Strict Trs:
  { minus(minus(x)) -> x
  , minus(h(x)) -> h(minus(x))
  , minus(f(x, y)) -> f(minus(y), minus(x)) }
Obligation:
  runtime complexity
Answer:
  YES(?,O(n^1))

The problem is match-bounded by 1. The enriched problem is
compatible with the following automaton.
{ minus_0(2) -> 1
, minus_1(2) -> 3
, h_0(2) -> 2
, h_1(3) -> 1
, h_1(3) -> 3
, f_0(2, 2) -> 2
, f_1(3, 3) -> 1
, f_1(3, 3) -> 3 }

Hurray, we answered YES(?,O(n^1))