+let compare_node tree a b =
+ compare (Naive_tree.preorder tree a ) (Naive_tree.preorder tree b )
+
+module Tas = struct
+type 'a tas =
+ | Vide
+ | Noeud of 'a tas * 'a * 'a tas
+
+let comp_node tree a b = (Naive_tree.preorder tree a )< (Naive_tree.preorder tree b )
+
+let rec size t =
+ match t with
+ Vide -> 0
+ | Noeud (t1,racine,t2) -> 1+ size t1 + size t2
+
+let rec height t =
+ match t with
+ Vide -> 0
+ | Noeud (t1,racine,t2) -> 1 + max (height t1) (height t2)
+
+let equilibre t =
+ let rec aux t =
+ match t with
+ Vide -> 0
+ | Noeud (t1,racine,t2) -> 1 + min (aux t1) (aux t2)
+ in
+ let max_h = height t in
+ let min_h = aux t in
+ if max_h- min_h >1 then false
+ else true
+
+let is_tas t =
+ if not (equilibre t) then false
+ else
+ let rec aux n t =
+ match t with
+ Vide -> true
+ | Noeud (Vide,racine,Vide) -> racine >= n
+ | Noeud (t1,racine, t2) -> (aux racine t1) && (aux racine t2)
+ in
+ aux 0 t
+
+let rec pop tree t =
+ match t with
+ Vide -> failwith "Tas vide"
+ | Noeud (t1, racine, t2) -> begin
+ match t1,t2 with
+ Vide,t2 -> t2
+ | t1,Vide -> t1
+ | Noeud (t3,r1,t4),Noeud (t5,r2,t6) -> if comp_node tree r1 r2 then Noeud (pop tree t1, r1,t2)
+ else Noeud (pop tree t2, r2, t1)
+ end
+
+let rec push tree t a =
+ match t with
+ Vide -> Noeud(Vide,a,Vide)
+ | Noeud (t1,r,t2) -> if comp_node tree a r then Noeud (t2,a,push tree t1 r)
+ else Noeud(t2,r, push tree t1 a)
+
+let tas_of_list tree l =
+ List.fold_left (push tree) Vide l
+
+let is_empty t = (size t )== 0