diff --git a/Makefile b/Makefile
index 6c7bd58..40887a5 100644
--- a/Makefile
+++ b/Makefile
@@ -6,7 +6,7 @@
 #    By: gbrochar <marvin@42.fr>                    +#+  +:+       +#+         #
 #                                                 +#+#+#+#+#+   +#+            #
 #    Created: 2015/11/27 19:26:17 by gbrochar          #+#    #+#              #
-#    Updated: 2024/10/13 18:44:22 by gbrochar         ###   ########.fr        #
+#    Updated: 2024/10/14 20:59:43 by gbrochar         ###   ########.fr        #
 #                                                                              #
 # **************************************************************************** #
 
@@ -22,7 +22,7 @@ ft_strchr.c ft_strclr.c ft_strcmp.c ft_strcpy.c ft_strdel.c ft_strdup.c \
 ft_strequ.c ft_striter.c ft_striteri.c ft_strjoin.c ft_strlcat.c ft_strlen.c \
 ft_strmap.c ft_strmapi.c ft_strncat.c ft_strncmp.c ft_strncpy.c ft_strnequ.c \
 ft_strnew.c ft_strnstr.c ft_strrchr.c ft_strsplit.c ft_strstr.c ft_strsub.c \
-ft_strtrim.c ft_swap.c ft_tolower.c ft_toupper.c ft_lstadd_back.c
+ft_strtrim.c ft_swap.c ft_tolower.c ft_toupper.c ft_lstadd_back.c ft_lstinsert.c
 
 OBJ = $(SRC:.c=.o)
 
diff --git a/ft_lstadd_back.c b/ft_lstadd_back.c
index 750452d..91c6e10 100644
--- a/ft_lstadd_back.c
+++ b/ft_lstadd_back.c
@@ -2,6 +2,10 @@
 
 void	ft_lstadd_back(t_list **alst, t_list *new)
 {
+	if (!alst) {
+		(*alst) = new;
+		return;
+	}
 	while ((*alst)->next)
 		alst = &(*alst)->next;
 	(*alst)->next = new;
diff --git a/ft_lstinsert.c b/ft_lstinsert.c
new file mode 100644
index 0000000..e1fd61e
--- /dev/null
+++ b/ft_lstinsert.c
@@ -0,0 +1,14 @@
+#include "libft.h"
+
+void ft_lstinsert(t_list **lst, t_list *new, int (*f)(t_list *a, t_list *b)) {
+	if (!(*lst)) {
+		*lst = new;
+		return;
+	}
+	while ((*lst)->next && f(new, *lst) < 0) {
+		lst = &(*lst)->next;
+	}
+	t_list *tmp = (*lst)->next;
+	(*lst)->next = new;
+	new->next = tmp;
+}
diff --git a/libft.h b/libft.h
index 53a8fbd..35acffe 100644
--- a/libft.h
+++ b/libft.h
@@ -6,7 +6,7 @@
 /*   By: gbrochar <marvin@42.fr>                    +#+  +:+       +#+        */
 /*                                                +#+#+#+#+#+   +#+           */
 /*   Created: 2015/11/24 12:52:28 by gbrochar          #+#    #+#             */
-/*   Updated: 2024/10/13 18:45:37 by gbrochar         ###   ########.fr       */
+/*   Updated: 2024/10/14 21:01:47 by gbrochar         ###   ########.fr       */
 /*                                                                            */
 /* ************************************************************************** */
 
@@ -26,6 +26,7 @@ typedef struct		s_list
 
 void				ft_lstadd(t_list **alst, t_list *new);
 void				ft_lstadd_back(t_list **alst, t_list *new);
+void				ft_lstinsert(t_list **lst, t_list *new, int (*f)(t_list *a, t_list *b));
 void				ft_lstdel(t_list **alst, void (*del)(void *, size_t));
 void				ft_lstdelone(t_list **alst, void (*del)(void *, size_t));
 t_list				*ft_lstnew(void const *content, size_t content_size);