339 lines
11 KiB
OCaml
339 lines
11 KiB
OCaml
(***********************************************************************)
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(* *)
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(* OCaml *)
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(* *)
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(* Xavier Leroy, projet Cristal, INRIA Rocquencourt *)
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(* *)
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(* Copyright 1996 Institut National de Recherche en Informatique et *)
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(* en Automatique. All rights reserved. This file is distributed *)
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(* under the terms of the GNU Library General Public License, with *)
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(* the special exception on linking described in file ../LICENSE. *)
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(* *)
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(***********************************************************************)
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(* $Id$ *)
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module type OrderedType =
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sig
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type t
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val compare: t -> t -> int
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end
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module type S =
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sig
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type key
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type +'a t
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val empty: 'a t
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val is_empty: 'a t -> bool
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val mem: key -> 'a t -> bool
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val add: key -> 'a -> 'a t -> 'a t
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val singleton: key -> 'a -> 'a t
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val remove: key -> 'a t -> 'a t
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val merge: (key -> 'a option -> 'b option -> 'c option) -> 'a t -> 'b t -> 'c t
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val compare: ('a -> 'a -> int) -> 'a t -> 'a t -> int
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val equal: ('a -> 'a -> bool) -> 'a t -> 'a t -> bool
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val iter: (key -> 'a -> unit) -> 'a t -> unit
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val fold: (key -> 'a -> 'b -> 'b) -> 'a t -> 'b -> 'b
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val for_all: (key -> 'a -> bool) -> 'a t -> bool
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val exists: (key -> 'a -> bool) -> 'a t -> bool
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val filter: (key -> 'a -> bool) -> 'a t -> 'a t
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val partition: (key -> 'a -> bool) -> 'a t -> 'a t * 'a t
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val cardinal: 'a t -> int
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val bindings: 'a t -> (key * 'a) list
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val min_binding: 'a t -> (key * 'a)
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val max_binding: 'a t -> (key * 'a)
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val choose: 'a t -> (key * 'a)
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val split: key -> 'a t -> 'a t * 'a option * 'a t
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val find: key -> 'a t -> 'a
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val map: ('a -> 'b) -> 'a t -> 'b t
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val mapi: (key -> 'a -> 'b) -> 'a t -> 'b t
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end
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module Make(Ord: OrderedType) = struct
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type key = Ord.t
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type 'a t =
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Empty
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| Node of 'a t * key * 'a * 'a t * int
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let height = function
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Empty -> 0
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| Node(_,_,_,_,h) -> h
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let create l x d r =
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let hl = height l and hr = height r in
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Node(l, x, d, r, (if hl >= hr then hl + 1 else hr + 1))
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let singleton x d = Node(Empty, x, d, Empty, 1)
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let bal l x d r =
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let hl = match l with Empty -> 0 | Node(_,_,_,_,h) -> h in
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let hr = match r with Empty -> 0 | Node(_,_,_,_,h) -> h in
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if hl > hr + 2 then begin
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match l with
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Empty -> invalid_arg "Map.bal"
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| Node(ll, lv, ld, lr, _) ->
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if height ll >= height lr then
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create ll lv ld (create lr x d r)
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else begin
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match lr with
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Empty -> invalid_arg "Map.bal"
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| Node(lrl, lrv, lrd, lrr, _)->
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create (create ll lv ld lrl) lrv lrd (create lrr x d r)
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end
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end else if hr > hl + 2 then begin
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match r with
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Empty -> invalid_arg "Map.bal"
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| Node(rl, rv, rd, rr, _) ->
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if height rr >= height rl then
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create (create l x d rl) rv rd rr
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else begin
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match rl with
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Empty -> invalid_arg "Map.bal"
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| Node(rll, rlv, rld, rlr, _) ->
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create (create l x d rll) rlv rld (create rlr rv rd rr)
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end
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end else
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Node(l, x, d, r, (if hl >= hr then hl + 1 else hr + 1))
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let empty = Empty
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let is_empty = function Empty -> true | _ -> false
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let rec add x data = function
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Empty ->
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Node(Empty, x, data, Empty, 1)
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| Node(l, v, d, r, h) ->
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let c = Ord.compare x v in
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if c = 0 then
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Node(l, x, data, r, h)
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else if c < 0 then
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bal (add x data l) v d r
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else
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bal l v d (add x data r)
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let rec find x = function
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Empty ->
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raise Not_found
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| Node(l, v, d, r, _) ->
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let c = Ord.compare x v in
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if c = 0 then d
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else find x (if c < 0 then l else r)
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let rec mem x = function
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Empty ->
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false
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| Node(l, v, d, r, _) ->
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let c = Ord.compare x v in
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c = 0 || mem x (if c < 0 then l else r)
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let rec min_binding = function
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Empty -> raise Not_found
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| Node(Empty, x, d, r, _) -> (x, d)
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| Node(l, x, d, r, _) -> min_binding l
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let rec max_binding = function
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Empty -> raise Not_found
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| Node(l, x, d, Empty, _) -> (x, d)
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| Node(l, x, d, r, _) -> max_binding r
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let rec remove_min_binding = function
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Empty -> invalid_arg "Map.remove_min_elt"
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| Node(Empty, x, d, r, _) -> r
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| Node(l, x, d, r, _) -> bal (remove_min_binding l) x d r
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let merge t1 t2 =
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match (t1, t2) with
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(Empty, t) -> t
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| (t, Empty) -> t
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| (_, _) ->
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let (x, d) = min_binding t2 in
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bal t1 x d (remove_min_binding t2)
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let rec remove x = function
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Empty ->
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Empty
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| Node(l, v, d, r, h) ->
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let c = Ord.compare x v in
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if c = 0 then
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merge l r
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else if c < 0 then
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bal (remove x l) v d r
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else
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bal l v d (remove x r)
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let rec iter f = function
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Empty -> ()
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| Node(l, v, d, r, _) ->
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iter f l; f v d; iter f r
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let rec map f = function
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Empty ->
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Empty
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| Node(l, v, d, r, h) ->
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let l' = map f l in
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let d' = f d in
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let r' = map f r in
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Node(l', v, d', r', h)
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let rec mapi f = function
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Empty ->
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Empty
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| Node(l, v, d, r, h) ->
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let l' = mapi f l in
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let d' = f v d in
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let r' = mapi f r in
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Node(l', v, d', r', h)
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let rec fold f m accu =
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match m with
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Empty -> accu
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| Node(l, v, d, r, _) ->
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fold f r (f v d (fold f l accu))
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let rec for_all p = function
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Empty -> true
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| Node(l, v, d, r, _) -> p v d && for_all p l && for_all p r
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let rec exists p = function
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Empty -> false
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| Node(l, v, d, r, _) -> p v d || exists p l || exists p r
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(* Beware: those two functions assume that the added k is *strictly*
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smaller (or bigger) than all the present keys in the tree; it
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does not test for equality with the current min (or max) key.
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Indeed, they are only used during the "join" operation which
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respects this precondition.
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*)
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let rec add_min_binding k v = function
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| Empty -> singleton k v
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| Node (l, x, d, r, h) ->
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bal (add_min_binding k v l) x d r
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let rec add_max_binding k v = function
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| Empty -> singleton k v
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| Node (l, x, d, r, h) ->
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bal l x d (add_max_binding k v r)
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(* Same as create and bal, but no assumptions are made on the
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relative heights of l and r. *)
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let rec join l v d r =
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match (l, r) with
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(Empty, _) -> add_min_binding v d r
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| (_, Empty) -> add_max_binding v d l
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| (Node(ll, lv, ld, lr, lh), Node(rl, rv, rd, rr, rh)) ->
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if lh > rh + 2 then bal ll lv ld (join lr v d r) else
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if rh > lh + 2 then bal (join l v d rl) rv rd rr else
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create l v d r
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(* Merge two trees l and r into one.
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All elements of l must precede the elements of r.
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No assumption on the heights of l and r. *)
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let concat t1 t2 =
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match (t1, t2) with
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(Empty, t) -> t
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| (t, Empty) -> t
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| (_, _) ->
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let (x, d) = min_binding t2 in
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join t1 x d (remove_min_binding t2)
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let concat_or_join t1 v d t2 =
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match d with
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| Some d -> join t1 v d t2
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| None -> concat t1 t2
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let rec split x = function
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Empty ->
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(Empty, None, Empty)
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| Node(l, v, d, r, _) ->
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let c = Ord.compare x v in
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if c = 0 then (l, Some d, r)
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else if c < 0 then
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let (ll, pres, rl) = split x l in (ll, pres, join rl v d r)
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else
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let (lr, pres, rr) = split x r in (join l v d lr, pres, rr)
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let rec merge f s1 s2 =
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match (s1, s2) with
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(Empty, Empty) -> Empty
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| (Node (l1, v1, d1, r1, h1), _) when h1 >= height s2 ->
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let (l2, d2, r2) = split v1 s2 in
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concat_or_join (merge f l1 l2) v1 (f v1 (Some d1) d2) (merge f r1 r2)
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| (_, Node (l2, v2, d2, r2, h2)) ->
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let (l1, d1, r1) = split v2 s1 in
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concat_or_join (merge f l1 l2) v2 (f v2 d1 (Some d2)) (merge f r1 r2)
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| _ ->
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assert false
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let rec filter p = function
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Empty -> Empty
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| Node(l, v, d, r, _) ->
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(* call [p] in the expected left-to-right order *)
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let l' = filter p l in
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let pvd = p v d in
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let r' = filter p r in
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if pvd then join l' v d r' else concat l' r'
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let rec partition p = function
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Empty -> (Empty, Empty)
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| Node(l, v, d, r, _) ->
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(* call [p] in the expected left-to-right order *)
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let (lt, lf) = partition p l in
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let pvd = p v d in
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let (rt, rf) = partition p r in
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if pvd
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then (join lt v d rt, concat lf rf)
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else (concat lt rt, join lf v d rf)
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type 'a enumeration = End | More of key * 'a * 'a t * 'a enumeration
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let rec cons_enum m e =
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match m with
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Empty -> e
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| Node(l, v, d, r, _) -> cons_enum l (More(v, d, r, e))
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let compare cmp m1 m2 =
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let rec compare_aux e1 e2 =
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match (e1, e2) with
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(End, End) -> 0
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| (End, _) -> -1
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| (_, End) -> 1
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| (More(v1, d1, r1, e1), More(v2, d2, r2, e2)) ->
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let c = Ord.compare v1 v2 in
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if c <> 0 then c else
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let c = cmp d1 d2 in
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if c <> 0 then c else
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compare_aux (cons_enum r1 e1) (cons_enum r2 e2)
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in compare_aux (cons_enum m1 End) (cons_enum m2 End)
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let equal cmp m1 m2 =
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let rec equal_aux e1 e2 =
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match (e1, e2) with
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(End, End) -> true
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| (End, _) -> false
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| (_, End) -> false
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| (More(v1, d1, r1, e1), More(v2, d2, r2, e2)) ->
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Ord.compare v1 v2 = 0 && cmp d1 d2 &&
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equal_aux (cons_enum r1 e1) (cons_enum r2 e2)
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in equal_aux (cons_enum m1 End) (cons_enum m2 End)
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let rec cardinal = function
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Empty -> 0
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| Node(l, _, _, r, _) -> cardinal l + 1 + cardinal r
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let rec bindings_aux accu = function
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Empty -> accu
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| Node(l, v, d, r, _) -> bindings_aux ((v, d) :: bindings_aux accu r) l
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let bindings s =
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bindings_aux [] s
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let choose = min_binding
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end
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