optimize swap

src/swap.c

@@ -19,7 +19,10 @@
  * @param yp Segundo valor
  */
 void swap(int *xp, int *yp) {
-	int temp = *xp;
-	*xp = *yp;
-	*yp = temp;
+	if (xp == yp) {
+		return;
+	}
+	*xp = *xp + *yp;
+	*yp = *xp - *yp;
+	*xp = *xp - *yp;
 }