init output map in some way

src/dancing_links.c

@@ -211,6 +211,9 @@ void    print_solution(t_list *sol, t_node *root, int amount)
 
     map_size = root->size * root->size + 1;
     map = malloc(sizeof(char) * map_size);
+    // init with zeroes by ft_memalloc
+    // or in some other way.
+    // map can contain garbage
     map[map_size] = 0;
     while (sol)
     {