* Step 1: Bounds WORST_CASE(?,O(n^1))
    + Considered Problem:
        - Strict TRS:
            ++(x,nil()) -> x
            ++(nil(),y) -> y
            flatten(nil()) -> nil()
            flatten(unit(x)) -> flatten(x)
            rev(nil()) -> nil()
            rev(unit(x)) -> unit(x)
        - Signature:
            {++/2,flatten/1,rev/1} / {nil/0,unit/1}
        - Obligation:
            innermost runtime complexity wrt. defined symbols {++,flatten,rev} and constructors {nil,unit}
    + Applied Processor:
        Bounds {initialAutomaton = minimal, enrichment = match}
    + Details:
        The problem is match-bounded by 1.
        The enriched problem is compatible with follwoing automaton.
          ++_0(2,2) -> 1
          flatten_0(2) -> 1
          flatten_1(2) -> 1
          nil_0() -> 1
          nil_0() -> 2
          nil_1() -> 1
          rev_0(2) -> 1
          unit_0(2) -> 1
          unit_0(2) -> 2
          unit_1(2) -> 1
          2 -> 1
* Step 2: EmptyProcessor WORST_CASE(?,O(1))
    + Considered Problem:
        - Weak TRS:
            ++(x,nil()) -> x
            ++(nil(),y) -> y
            flatten(nil()) -> nil()
            flatten(unit(x)) -> flatten(x)
            rev(nil()) -> nil()
            rev(unit(x)) -> unit(x)
        - Signature:
            {++/2,flatten/1,rev/1} / {nil/0,unit/1}
        - Obligation:
            innermost runtime complexity wrt. defined symbols {++,flatten,rev} and constructors {nil,unit}
    + Applied Processor:
        EmptyProcessor
    + Details:
        The problem is already closed. The intended complexity is O(1).

WORST_CASE(?,O(n^1))