vault backup: 2023-09-25 13:35:25

Algo/Séminaire/Exercices seminaire.md

@@ -383,7 +383,7 @@ let rec puissance_better x n =
 	else
 		let pb_odd = puissance_better x (n/2) * n in pb_odd*pb_odd;;
 
-(*Correction*)
+(*Correction v1*)
 let power x n = match n with
 	| 0 -> (match x with
 		| 0. -> failwith "power 0^0 impossible"
@@ -395,5 +395,19 @@ let power x n = match n with
 		| _ -> (let rec p = function
 			| 0 -> 1.
 			| n -> x*.p(n-1) in p n)
-	;;
+;;
+
+(*Correction v2*)
+let power x n = match n with
+	| 0 -> (match x with
+		| 0. -> failwith "power 0^0 impossible"
+		| _ -> 1.)
+	| _ -> (match x with 
+		| 1. -> 1.
+		| 0. -> 0.
+		| -1. -> if n mod 2 = 0 then 1. else -1.)
+		| _ -> (let rec p = function
+			| 0 -> 1.
+			| n -> x*.p(n-1) in p n)
+;;
 ```