From 47516dbf42fb5edf554619d53b632401217fd468 Mon Sep 17 00:00:00 2001
From: Arkitu <git@arkitu.fr>
Date: Mon, 12 Jan 2026 22:12:54 +0100
Subject: [PATCH] td5 exo3

---
 td5/ocaml/lib/lib.ml   | 29 +++++++++++++++++++++++++++++
 td5/ocaml/test/test.ml |  1 +
 2 files changed, 30 insertions(+)

diff --git a/td5/ocaml/lib/lib.ml b/td5/ocaml/lib/lib.ml
index 6ed633e..9f76a98 100644
--- a/td5/ocaml/lib/lib.ml
+++ b/td5/ocaml/lib/lib.ml
@@ -27,3 +27,32 @@ let rec selection_sort l = match l with
     let m, q = min_l l in
     m::(selection_sort q)
 ;;
+
+(* Exercice 3 *)
+let rec split l n =
+  if n = 0 then [], l
+  else match l with
+    | [] -> failwith "Splitting empty list"
+    | a::q ->
+      let qa, lb = split q (n-1) in
+      a::qa, lb
+;;
+
+let rec fuse la lb = match la, lb with
+  | [], _ -> lb
+  | _, [] -> la
+  | a::qa, b::qb ->
+    if a > b then
+      b::(fuse la qb)
+    else
+      a::(fuse qa lb)
+;;
+
+let rec fusion_sort l =
+  let n = List.length l in
+  if n <= 1 then l else
+  let la, lb = split l (n/2) in
+  let sa = fusion_sort la in
+  let sb = fusion_sort lb in
+  fuse sa sb
+;;
diff --git a/td5/ocaml/test/test.ml b/td5/ocaml/test/test.ml
index 4707118..48493bd 100644
--- a/td5/ocaml/test/test.ml
+++ b/td5/ocaml/test/test.ml
@@ -5,3 +5,4 @@ let sorted = [0; 0; 3; 5; 5; 9];;
 
 assert (insertion_sort l = sorted);;
 assert (selection_sort l = sorted);;
+assert (fusion_sort l = sorted);;