98 lines
2.6 KiB
OCaml
98 lines
2.6 KiB
OCaml
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 add: key -> 'a -> 'a t -> 'a t
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val find: key -> 'a t -> 'a
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val iter: (key -> 'a -> 'b) -> 'a t -> unit
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val fold: (key -> 'a -> 'b -> 'b) -> 'a t -> 'b -> 'b
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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 empty = Empty
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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 new 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 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 "Set.bal"
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| Node(ll, lv, ld, lr, _) ->
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if height ll >= height lr then
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new ll lv ld (new lr x d r)
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else begin
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match lr with
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Empty -> invalid_arg "Set.bal"
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| Node(lrl, lrv, lrd, lrr, _)->
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new (new ll lv ld lrl) lrv lrd (new 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 "Set.bal"
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| Node(rl, rv, rd, rr, _) ->
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if height rr >= height rl then
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new (new 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 "Set.bal"
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| Node(rll, rlv, rld, rlr, _) ->
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new (new l x d rll) rlv rld (new 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 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) as t ->
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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 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 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 l (f v d (fold f r accu))
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end
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