From 4fa3783722515eb5a7656955b168c0022c2e77d4 Mon Sep 17 00:00:00 2001
From: Louis <me@louisgallet.fr>
Date: Fri, 6 Oct 2023 14:26:13 +0200
Subject: [PATCH] vault backup: 2023-10-06 14:26:13

---
 Algo/Courses/Chapter 6 - Lists (Exercises).md | 25 +++++++++++++------
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/Algo/Courses/Chapter 6 - Lists (Exercises).md b/Algo/Courses/Chapter 6 - Lists (Exercises).md
index 0572dec..2d8c5a7 100644
--- a/Algo/Courses/Chapter 6 - Lists (Exercises).md	
+++ b/Algo/Courses/Chapter 6 - Lists (Exercises).md	
@@ -1,13 +1,13 @@
 ## 1.1 - Product
 
 ```Ocaml
-let rec product = function
+# let rec product = function
 	| [] -> 0
 	| x::t -> x * product t;;
 ```
 ## 1.2 - Count
 ```Ocaml
-let rec count x n =
+# let rec count x n =
 	if x = [] then
 		0
 	else
@@ -16,11 +16,16 @@ let rec count x n =
 			1 + count t n
 		else
 			count t n;;
+(* Correction *)
+# let rec count x = function
+	| [] -> 0
+	| e::t -> (if x = e then 1 else 0) + count x t;;
+val count = 'a -> 'a list -> int = <fun>
 ```
 
 ## 1.3 - Search
 ```Ocaml
-let rec search x n =
+# let rec search x n =
 	if x = [] then
 		0
 	else
@@ -29,17 +34,23 @@ let rec search x n =
 			true
 		else
 			search t n;;
+(* Correction *)
+# let search x = function
+	| [] -> false
+	| e::t when x = e -> true
+	| _::t -> search x t ;;
+val search 'a -> 'a list -> bool = <fun>
 ```
 
 ## 1.4 - $n^{th}$
 ```Ocaml
-let rec length l = 
+# let rec length l = 
 	if l = [] then
 		0
 	else
 		let e::t = l in
 			1 + length t;;
-let rec nth x n =
+# let rec nth x n =
 	if (x = [] || n =< 0) then
 		Invalid_arg "The number of element in the list is 0"
 	else if length x < n then
@@ -54,7 +65,7 @@ let rec nth x n =
 
 ## 1.5 - Maximum
 ```Ocaml
-let rec max_value list = match list with 
+# let rec max_value list = match list with 
 	| [] -> failwith "La liste est vide" 
 	| [x] -> x 
 	| hd :: tl -> 
@@ -64,7 +75,7 @@ let rec max_value list = match list with
 
 ## 1.6 - Bonus second
 ```Ocaml
-let rec second_smallest list =
+# let rec second_smallest list =
   match list with
   | [] | [_] -> failwith "La liste ne contient pas au moins deux éléments distincts"
   | [x; y] -> if x < y then y else x