diff --git a/cv4/list_ops.c b/cv4/list_ops.c
index 9f58a2b..7343a68 100644
--- a/cv4/list_ops.c
+++ b/cv4/list_ops.c
@@ -5,14 +5,17 @@
 #include <string.h>
 
 list_t *new_list(size_t length, list_element_t elements[]) {
-    list_t *list = malloc(sizeof(list_t) + length * sizeof(list_element_t));
+    list_t *list = malloc(sizeof(list_t));
     if (!list) {
-        return NULL; 
+        return NULL;
+    }
+    list->elements = malloc(length * sizeof(list_element_t));
+    if (!list->elements) {
+        free(list);
+        return NULL;
     }
     list->length = length;
-    for (size_t i = 0; i < length; i++) {
-        list->elements[i] = elements[i];
-    }
+    memcpy(list->elements, elements, length * sizeof(list_element_t));
     return list;
 }
 
@@ -21,27 +24,25 @@ list_t *append_list(list_t *list1, list_t *list2) {
     if (!list3) {
         return NULL;
     }
-
-    for (size_t i = list1->length; i < list3->length; i++)
-        list3->elements[i] = list2->elements[i - list1->length];
+    memcpy(list3->elements + list1->length, list2->elements, list2->length * sizeof(list_element_t));
+    list3->length = list1->length + list2->length;
     return list3;
 }
 
 list_t *filter_list(list_t *list, bool (*predicate)(list_element_t)) {
-   list_element_t fil[list->length];
-   size_t filter_length = 0;
-   for(size_t i = 0; i < list->length;i++){
-     if(predicate(list->elements[i])){
-       fil[filter_length++] = list->elements[i];
-   	}
-   }
-   list_t *result = new_list(filter_length,fil);
-    if (result == NULL) {
-        return NULL; 
+    list_element_t *filtered_elements = malloc(list->length * sizeof(list_element_t));
+    if (!filtered_elements) {
+        return NULL;
     }
-   for(size_t i = 0;i < list->length;i++)
-   		result->elements[i] = fil[i];
-   return result;
+    size_t filter_length = 0;
+    for (size_t i = 0; i < list->length; i++) {
+        if (predicate(list->elements[i])) {
+            filtered_elements[filter_length++] = list->elements[i];
+        }
+    }
+    list_t *result = new_list(filter_length, filtered_elements);
+    free(filtered_elements);
+    return result;
 }
 
 size_t length_list(list_t *list) {