le 0 y true le s x 0 false le s x s y le x y app nil y y app add n x y add n app x y low n nil nil low n add m x if_low le m n n add m x if_low true n add m x add m low n x if_low false n add m x low n x high n nil nil high n add m x if_high le m n n add m x if_high true n add m x high n x if_high false n add m x add m high n x head add n x n tail add n x x isempty nil true isempty add n x false quicksort x if_qs isempty x low head x tail x head x high head x tail x if_qs true x n y nil if_qs false x n y app quicksort x add n quicksort y le 2 0 0 true 0 s 1 false 0 app 2 nil 0 add 2 low 2 if_low 3 high 2 if_high 3 head 1 tail 1 isempty 1 quicksort 1 if_qs 4 FULL ./TRS/Thiemann/quicksort.trs