1 files changed, 20 insertions, 0 deletions
diff --git a/lib/segmenttree.mli b/lib/segmenttree.mli
new file mode 100644
index 00000000..4aea13e9
--- /dev/null
+++ b/lib/segmenttree.mli
@@ -0,0 +1,20 @@
+(** This module is a very simple implementation of "segment trees".
+
+    A segment tree of type ['a t] represents a mapping from a union of
+    disjoint segments to some values of type 'a. 
+*)
+
+(** A mapping from a union of disjoint segments to some values of type ['a]. *)
+type 'a t
+
+(** [make [(i1, j1), v1; (i2, j2), v2; ...] creates a mapping that
+    associates to every integer [x] the value [v1] if [i1 <= x <= j1],
+    [v2] if [i2 <= x <= j2], and so one. 
+    Precondition: the segments must be sorted. *)
+val make : ((int * int) * 'a) list -> 'a t
+
+(** [lookup k t] looks for an image for key [k] in the interval tree [t]. 
+    Raise [Not_found] if it fails. *)
+val lookup : int -> 'a t -> 'a
+
+