diff --git a/Makefile b/Makefile
index 05e55b2..16a7a94 100644
--- a/Makefile
+++ b/Makefile
@@ -6,7 +6,7 @@
 #    By: gtertysh <marvin@42.fr>                    +#+  +:+       +#+         #
 #                                                 +#+#+#+#+#+   +#+            #
 #    Created: 2016/12/14 16:54:48 by gtertysh          #+#    #+#              #
-#    Updated: 2016/12/20 20:37:58 by gtertysh         ###   ########.fr        #
+#    Updated: 2016/12/22 18:18:36 by gtertysh         ###   ########.fr        #
 #                                                                              #
 # **************************************************************************** #
 
@@ -45,7 +45,7 @@ LIBFLAGS = -lft -L $(LIBFOLDER)
 
 LIBFOLDER = ./libft/
 
-FLAGS = -Werror -Wextra -Wall
+FLAGS = -Werror -Wextra -Wall -O2
 
 CC = clang
 
diff --git a/inc/fillit.h b/inc/fillit.h
index 273b06d..c4a5a5b 100644
--- a/inc/fillit.h
+++ b/inc/fillit.h
@@ -97,9 +97,9 @@ void            add_row(int *col_numbers, t_node **cols_arr, t_coord coord, int
 
 void			search(t_node* root, t_node **solution, int k, int amount);
 
-void			cover(t_node *to_cover);
+int			    cover(t_node *to_cover);
 
-void			uncover(t_node *to_uncover);
+int 			uncover(t_node *to_uncover);
 
 int				*get_types(char **ttr);
 
@@ -109,4 +109,6 @@ unsigned int    ft_sqrt_ceil(unsigned int num);
 
 void			fill_map(char *map, int size, t_node *ttr, int letter);
 
+void            init(char **argv);
+
 #endif
diff --git a/src/dancing_links.c b/src/dancing_links.c
index f2609fd..977a2dc 100644
--- a/src/dancing_links.c
+++ b/src/dancing_links.c
@@ -146,7 +146,7 @@ void    add_rows(int *types, int amount, int size, t_node **cols_arr)
     }
 }
 
-void    cover(t_node *to_cover)
+int    cover(t_node *to_cover)
 {
     static t_node    *step_vert;
     static t_node  *step_horiz;
@@ -164,9 +164,10 @@ void    cover(t_node *to_cover)
         }
         step_vert = step_vert->down;
     }
+    return (1);
 }
 
-void    uncover(t_node *to_uncover)
+int    uncover(t_node *to_uncover)
 {
     static t_node   *step_vert;
     static t_node *step_horiz;
@@ -185,6 +186,7 @@ void    uncover(t_node *to_uncover)
     }
     to_uncover->left->right = to_uncover;
     to_uncover->right->left = to_uncover;
+    return (1);
 }
 
 void    fill_map(char *map, int size, t_node *ttr, int letter)
@@ -244,18 +246,12 @@ void	search(t_node* root,t_node **solution, int k, int amount)
     {
         solution[k] = row;
         j = row->right;
-        while (j != row)
-        {
-            cover(j->column);
+        while (j != row && cover(j->column))
             j = j->right;
-        }
         search(root, solution, k + 1, amount);
         j = row->left;
-        while (j != row)
-        {
-            uncover(j->column);
+        while (j != row && uncover(j->column))
             j = j->left;
-        }
         row = row->down;
     }
     uncover(current_col);
diff --git a/src/main.c b/src/main.c
index 976f37c..0b6f6c9 100644
--- a/src/main.c
+++ b/src/main.c
@@ -13,7 +13,9 @@
 #include "fillit.h"
 
 /*
-**	bad global variable 
+**  definition of global variable
+**  that contains all possible tetrominoes
+**  inside 4x4 square with initial coordinates at [0][0]
 */
 
 t_ttrmn	g_templates[19] = 
@@ -54,16 +56,14 @@ int		main(int argc, char **argv)
 
 	ans = NULL;
 	i = 0;
-	if (argc != 2)
-	{
-		ft_putstr("error\n");
-		return (1);
-	}
-	if (!(string = read_file(argv[1])))
-	{
-		ft_putstr("error\n");
-		return (1);
-	}	//printf("string:\n\n\n%s\n", string);
+
+    if (argc != 2)
+        ft_putstr("error\n");
+    else
+        init(argv[1]);
+
+    string = read_file(argv[1]);
+    //printf("string:\n\n\n%s\n", string);
 
 	table = to_table(&string);
 	//printf("print_table:\n\n\n");
diff --git a/tests/color b/tests/color
deleted file mode 100755
index 4ea5ef2..0000000
Binary files a/tests/color and /dev/null differ