diff --git a/.clang-format b/.clang-format
new file mode 100644
index 0000000..b344245
--- /dev/null
+++ b/.clang-format
@@ -0,0 +1,31 @@
+Language: C
+
+AlignConsecutiveDeclarations: false
+AlignConsecutiveMacros: false
+AlignEscapedNewlinesLeft: true
+AllowAllParametersOfDeclarationOnNextLine: false
+AllowShortBlocksOnASingleLine: false
+AllowShortFunctionsOnASingleLine: None
+AlwaysBreakAfterReturnType: None
+AlwaysBreakBeforeMultilineStrings: false
+BinPackArguments: true
+BinPackParameters: true
+BreakBeforeBraces: Allman
+BreakBeforeTernaryOperators: false
+ColumnLimit: 80
+IndentWidth: 4
+KeepEmptyLinesAtTheStartOfBlocks: false
+MaxEmptyLinesToKeep: 1
+PointerAlignment: Right
+PenaltyBreakBeforeFirstCallParameter: 1
+PenaltyBreakString: 1
+PenaltyExcessCharacter: 0
+SpaceAfterCStyleCast: true
+SpaceBeforeAssignmentOperators: true
+SpaceBeforeParens: ControlStatements
+SpaceInEmptyParentheses: false
+SpacesInCStyleCastParentheses: false
+SpacesInParentheses: false
+SpacesInSquareBrackets: false
+TabWidth: 4
+UseTab: Always
diff --git a/Makefile b/Makefile
index dded088..e1662ef 100644
--- a/Makefile
+++ b/Makefile
@@ -33,7 +33,7 @@ INSERTION = insertion.c
 FLAGS_FILES = algorithms_sort.c flag.c bench.c
 
 PARSING = ft_atoi.c parsing.c ft_strncmp.c ft_split.c ft_strlen.c ft_substr.c ft_itoa.c ft_isdigit.c \
-			ft_strjoin.c ft_strlcat.c ft_strlcpy.c parsing_2.c disorder.c
+			ft_strjoin.c ft_strlcat.c ft_strlcpy.c parsing_2.c disorder.c indexer.c
 
 CHECKER_FILES = check_error.c verif_flag.c verif_is_digit.c verif_overflow.c verif_double.c
 
diff --git a/algorithms/radix/radix.c b/algorithms/radix/radix.c
index 31e8a82..249c2d5 100644
--- a/algorithms/radix/radix.c
+++ b/algorithms/radix/radix.c
@@ -12,17 +12,17 @@
 
 #include "push_swap.h"
 
-static int	still_unit_value(t_stacks *stacks, int unit)
+static int	still_unit_index(t_stacks *stacks, int unit)
 {
 	t_stack	*temp;
 
 	temp = stacks->a;
-	if (!temp || temp->value >= unit)
+	if (!temp || temp->index >= unit)
 		return (1);
 	temp = temp->next;
 	while (temp != stacks->a)
 	{
-		if (temp->value >= unit)
+		if (temp->index >= unit)
 			return (1);
 		temp = temp->next;
 	}
@@ -43,9 +43,9 @@ static void	push_by_number_to_b(t_stacks *stacks, int unit, int nb)
 		temp = temp->next;
 	}
 	i = 0;
-	while (i < s_len && still_unit_value(stacks, unit))
+	while (i < s_len && still_unit_index(stacks, unit))
 	{
-		if (stacks->a && (stacks->a->value % (unit * 10)) / unit == nb)
+		if (stacks->a && (stacks->a->index % (unit * 10)) / unit == nb)
 			pb(stacks);
 		else
 			ra(stacks);
@@ -58,7 +58,7 @@ static void	rec_sort(t_stacks *stacks, int unit)
 	int	i;
 
 	i = 0;
-	if (!still_unit_value(stacks, unit))
+	if (!still_unit_index(stacks, unit))
 		return ;
 	while (i <= 9)
 	{
diff --git a/checker_linux b/checker_linux
new file mode 100755
index 0000000..002d593
Binary files /dev/null and b/checker_linux differ
diff --git a/flags/bench.c b/flags/bench.c
index 31b5d2a..9c59efe 100644
--- a/flags/bench.c
+++ b/flags/bench.c
@@ -31,7 +31,7 @@ static void	print_disorder(t_stacks *stacks)
 	secure_write(2, ".", 1);
 	if (ft_strlen(str) == 1)
 		secure_write(2, "0", 1);
-	secure_write(2, &str[ft_strlen(str) - 2], 2);
+	secure_write(2, &str[ft_strlen(str) - 2], ft_strlen(str) - 2);
 	secure_write(2, "%\n", 2);
 	free(str);
 }
diff --git a/includes/parsing.h b/includes/parsing.h
index 9beb240..8501ce0 100644
--- a/includes/parsing.h
+++ b/includes/parsing.h
@@ -34,5 +34,6 @@ int			ft_strlcat(char *dst, const char *src, int size);
 char		*join_all(int argc, char **argv);
 char		**split_all(char *tab);
 float		compute_disorder(char **strs, int pos);
+void		indexer(t_stacks *stacks);
 
 #endif
diff --git a/includes/push_swap.h b/includes/push_swap.h
index 9105eb4..ec6476f 100644
--- a/includes/push_swap.h
+++ b/includes/push_swap.h
@@ -16,6 +16,7 @@
 typedef struct s_stack
 {
 	int				value;
+	long long		index;
 	struct s_stack	*next;
 	struct s_stack	*previous;
 }	t_stack;
diff --git a/main.c b/main.c
index fbbec01..b4e75b5 100644
--- a/main.c
+++ b/main.c
@@ -32,7 +32,7 @@ int	main(int argc, char **argv)
 	if (check_error(tab, mod))
 		test1(tab, len, mod);
 	else
-		write(2, "Error\n", 7);
+		write(2, "Error\n", 6);
 	free_tab(tab);
 	return (0);
 }
diff --git a/parsing/indexer.c b/parsing/indexer.c
new file mode 100644
index 0000000..bdcc097
--- /dev/null
+++ b/parsing/indexer.c
@@ -0,0 +1,54 @@
+/* ************************************************************************** */
+/*                                                                            */
+/*                                                        :::      ::::::::   */
+/*   indexer.c                                          :+:      :+:    :+:   */
+/*                                                    +:+ +:+         +:+     */
+/*   By: dgaillet <dgaillet@student.42lyon.fr>      +#+  +:+       +#+        */
+/*                                                +#+#+#+#+#+   +#+           */
+/*   Created: 2026/01/14 10:14:06 by dgaillet          #+#    #+#             */
+/*   Updated: 2026/01/14 10:14:08 by dgaillet         ###   ########lyon.fr   */
+/*                                                                            */
+/* ************************************************************************** */
+
+#include "push_swap.h"
+
+static t_stack	*first_without_index(t_stack *stack)
+{
+	t_stack	*first;
+
+	if (stack->index < 0)
+		return (stack);
+	first = stack;
+	stack = stack->next;
+	while (stack != first)
+	{
+		if (stack->index < 0)
+			return (stack);
+		stack = stack->next;
+	}
+	return ((void *) 0);
+}
+
+void	indexer(t_stacks *stacks)
+{
+	int		i;
+	int		len;
+	t_stack	*lower;
+	t_stack	*temp;
+
+	i = 0;
+	len = stack_a_len(stacks);
+	while (i < len)
+	{
+		lower = first_without_index(stacks->a);
+		temp = lower->next;
+		while (temp != stacks->a)
+		{
+			if (lower->value > temp->value && temp->index < 0)
+				lower = temp;
+			temp = temp->next;
+		}
+		lower->index = i;
+		i++;
+	}
+}
diff --git a/secure_write.c b/secure_write.c
index cc75fcc..ddf01e1 100644
--- a/secure_write.c
+++ b/secure_write.c
@@ -6,7 +6,7 @@
 /*   By: dgaillet <dgaillet@student.42.fr>          +#+  +:+       +#+        */
 /*                                                +#+#+#+#+#+   +#+           */
 /*   Created: 2026/01/08 14:30:38 by dgaillet          #+#    #+#             */
-/*   Updated: 2026/01/09 12:05:56 by dgaillet         ###   ########lyon.fr   */
+/*   Updated: 2026/01/09 14:55:16 by dgaillet         ###   ########lyon.fr   */
 /*                                                                            */
 /* ************************************************************************** */
 
@@ -17,6 +17,6 @@ void	secure_write(int fd, char *str, int len)
 {
 	if (len < 0)
 		return ;
-	if (write(fd, str, len) < 0)
+	if (!str || write(fd, str, len) < 0)
 		exit (EXIT_FAILURE);
 }
diff --git a/stack_utils/stack_add.c b/stack_utils/stack_add.c
index 5effe0f..18006f3 100644
--- a/stack_utils/stack_add.c
+++ b/stack_utils/stack_add.c
@@ -21,6 +21,7 @@ t_stack	*new_stack(int value)
 	if (!new)
 		return (NULL);
 	new->value = value;
+	new->index = -1;
 	new->next = NULL;
 	new->previous = NULL;
 	return (new);
diff --git a/test_one.c b/test_one.c
index d909127..885422b 100644
--- a/test_one.c
+++ b/test_one.c
@@ -23,6 +23,7 @@ int	test1(char **tab, int len, int mod)
 	if (mod == -1)
 		return (0);
 	stacks = init_stacks(len, tab, mod);
+	indexer(stacks);
 	if (!stacks)
 		return (0);
 	if (check_order(stacks->a))