66 lines
1.7 KiB
OCaml
66 lines
1.7 KiB
OCaml
type 'a bstree = Leaf | Node of 'a * 'a bstree * 'a bstree;;
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let rec bstree_size t =
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match t with
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| Leaf -> 0
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| Node (_, l, r) ->
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1 + bstree_size l + bstree_size r;;
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let rec bstree_height t =
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match t with
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| Leaf -> 0
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| Node (_, l, r) ->
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1 + max (bstree_height l) (bstree_height r);;
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let bstree_empty = Leaf;;
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let bstree_is_empty t = t = Leaf;;
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let rec bstree_insert ~cmp x t =
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match t with
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| Leaf -> Node (x, Leaf, Leaf)
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| Node (x', l, r) when cmp x x' < 0 ->
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Node (x', bstree_insert ~cmp x l, r)
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| Node (x', l, r) when cmp x x' > 0 ->
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Node (x', l, bstree_insert ~cmp x r)
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| _ -> t;;
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let bstree_of_list ~cmp l =
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List.fold_left (Fun.flip (bstree_insert ~cmp)) Leaf l;;
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let rec bstree_mem ~cmp x t =
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match t with
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| Leaf -> false
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| Node (x', l, _) when cmp x x' < 0 ->
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bstree_mem ~cmp x l
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| Node (x', _, r) when cmp x x' > 0 ->
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bstree_mem ~cmp x r
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| _ -> true;;
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let rec bstree_largest t =
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match t with
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| Leaf -> failwith "bstree_largest: empty tree"
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| Node (x, _, Leaf) -> x
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| Node (_, _, r) -> bstree_largest r;;
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let rec bstree_smallest t =
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match t with
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| Leaf -> failwith "bstree_smallest: empty tree"
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| Node (x, Leaf, _) -> x
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| Node (_, l, _) -> bstree_smallest l;;
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let rec bstree_delete ~cmp x t =
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match t with
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| Leaf -> Leaf
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| Node (x', l, r) when cmp x x' < 0 ->
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Node (x', bstree_delete ~cmp x l, r)
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| Node (x', l, r) when cmp x x' > 0 ->
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Node (x', l, bstree_delete ~cmp x r)
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| Node (_, Leaf, Leaf) -> Leaf (* this does not need to be here, its a special case but ill leave it for clarity *)
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| Node (_, l, Leaf) -> l
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| Node (_, Leaf, r) -> r
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| Node (_, l, r) ->
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let succ = bstree_largest l in
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Node (succ, bstree_delete ~cmp succ l, r);;
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