YES
O(n^2)
TRS:
 {
     ++(x, nil()) -> x,
  ++(++(x, y), z) -> ++(x, ++(y, z)),
     ++(nil(), y) -> y,
   ++(.(x, y), z) -> .(x, ++(y, z))
 }
 DUP: We consider a non-duplicating system.
  Trs:
   {
       ++(x, nil()) -> x,
    ++(++(x, y), z) -> ++(x, ++(y, z)),
       ++(nil(), y) -> y,
     ++(.(x, y), z) -> .(x, ++(y, z))
   }
  Matrix Interpretation:
   Interpretation class: triangular
       [X3]  [X1]    [1 0][X3]   [1 0][X1]   [0]
   [.]([X2], [X0]) = [0 0][X2] + [0 1][X0] + [1]
   
           [1]
   [nil] = [1]
   
        [X3]  [X1]    [1 1][X3]   [1 0][X1]   [0]
   [++]([X2], [X0]) = [0 1][X2] + [0 1][X0] + [1]
   
   
   Qed