diff --git a/cv4/list_ops.c b/cv4/list_ops.c
index d59e10a..698d84f 100644
--- a/cv4/list_ops.c
+++ b/cv4/list_ops.c
@@ -1,53 +1,38 @@
+
+
 #include "list_ops.h"
 #include <stdlib.h>
-#include <stdbool.h>
+#include <string.h>
 
 list_t *new_list(size_t length, list_element_t elements[]) {
-    size_t size = sizeof(list_t) + length * sizeof(list_element_t);
-
-    list_t *resultList = (list_t *)malloc(size);
-
-    if (resultList == NULL) {
+    list_t *newList = (list_t *)malloc(sizeof(list_t) + length * sizeof(list_element_t));
+    if (newList == NULL) {
         return NULL;
     }
 
-    resultList->length = length;
+    newList->length = length;
+    memcpy(newList->elements, elements, length * sizeof(list_element_t));
 
-    for (size_t i = 0; i < length; ++i) {
-        resultList->elements[i] = elements[i];
-    }
-
-    return resultList;
+    return newList;
 }
 
 list_t *append_list(list_t *list1, list_t *list2) {
-    if (list1 == NULL) {
-        return (list2 != NULL) ? new_list(list2->length, list2->elements) : NULL;
-    }
-
-    if (list2 == NULL) {
-        return new_list(list1->length, list1->elements);
-    }
-
-    size_t totalSize = sizeof(list_t) + (list1->length + list2->length) * sizeof(list_element_t);
-
-    list_t *resultList = (list_t *)malloc(totalSize);
-
-    if (!resultList) {
+    if (list1 == NULL || list2 == NULL) {
         return NULL;
     }
 
-    resultList->length = list1->length + list2->length;
-
-    for (size_t i = 0; i < list1->length; ++i) {
-        resultList->elements[i] = list1->elements[i];
+    list_t *combinedList = (list_t *)malloc(sizeof(list_t) + (list1->length + list2->length) * sizeof(list_element_t));
+    if (combinedList == NULL) {
+        return NULL;
     }
 
-    for (size_t i = 0; i < list2->length; ++i) {
-        resultList->elements[list1->length + i] = list2->elements[i];
-    }
+    combinedList->length = list1->length + list2->length;
 
-    return resultList;
+    memcpy(combinedList->elements, list1->elements, list1->length * sizeof(list_element_t));
+
+    memcpy(combinedList->elements + list1->length, list2->elements, list2->length * sizeof(list_element_t));
+
+    return combinedList;
 }
 
 list_t *filter_list(list_t *list, bool (*filter)(list_element_t)) {
@@ -55,68 +40,41 @@ list_t *filter_list(list_t *list, bool (*filter)(list_element_t)) {
         return NULL;
     }
 
-    size_t count = 0;
-    for (size_t i = 0; i < list->length; ++i) {
-        if (filter(list->elements[i])) {
-            count++;
-        }
-    }
-
-    if (count == 0) {
-        return new_list(0, NULL);
-    }
-
-    size_t totalSize = sizeof(list_t) + count * sizeof(list_element_t);
-    list_t *filteredResult = (list_t *)malloc(totalSize);
-
-    if (!filteredResult) {
+    list_t *filteredList = (list_t *)malloc(sizeof(list_t) + list->length * sizeof(list_element_t));
+    if (filteredList == NULL) {
         return NULL;
     }
 
-    filteredResult->length = count;
+    size_t count = 0;
+    for (size_t i = 0; i < list->length; ++i) {
+        if (filter(list->elements[i])) {
+            ++count;
+        }
+    }
+
+    filteredList->length = count;
+
+    memcpy(filteredList->elements, list->elements, count * sizeof(list_element_t));
 
     size_t filteredIndex = 0;
     for (size_t i = 0; i < list->length; ++i) {
         if (filter(list->elements[i])) {
-            filteredResult->elements[filteredIndex] = list->elements[i];
-            filteredIndex++;
+            filteredList->elements[filteredIndex++] = list->elements[i];
         }
     }
 
-    return filteredResult;
+    return filteredList;
 }
 
 size_t length_list(list_t *list) {
     if (list == NULL) {
         return 0;
     }
-
     return list->length;
 }
 
-list_t *map_list(list_t *list, list_element_t (*map)(list_element_t)) {
-    if (list == NULL || map == NULL) {
-        return NULL;
-    }
-
-    list_t *mappedResult = new_list(list->length, NULL);
-
-    if (mappedResult == NULL) {
-        return NULL;
-    }
-
-    for (size_t i = 0; i < list->length; ++i) {
-        mappedResult->elements[i] = map(list->elements[i]);
-    }
-
-    return mappedResult;
-}
-
-
-list_element_t foldl_list(list_t *list, list_element_t initial,
-                          list_element_t (*foldl)(list_element_t,
-                                                  list_element_t)) {
-    if (list == NULL || foldl == NULL) {
+list_element_t foldl_list(list_t *list, list_element_t initial, list_element_t (*foldl)(list_element_t, list_element_t)) {
+    if (list == NULL) {
         return initial;
     }
 
@@ -129,38 +87,37 @@ list_element_t foldl_list(list_t *list, list_element_t initial,
     return result;
 }
 
-list_element_t foldr_list(list_t *list, list_element_t initial,
-                          list_element_t (*foldr)(list_element_t,
-                                                  list_element_t)) {
-    if (!list || !foldr) {
+list_element_t foldr_list(list_t *list, list_element_t initial, list_element_t (*foldr)(list_element_t, list_element_t)) {
+    if (list == NULL) {
         return initial;
     }
 
-    list_element_t foldResult = initial;
+    list_element_t result = initial;
 
-    for (size_t i = 0; i < list->length; ++i) {
-        foldResult = foldr(list->elements[list->length - 1 - i], foldResult);
+    for (size_t i = list->length; i > 0; --i) {
+        result = foldr(list->elements[i - 1], result);
     }
 
-    return foldResult;
+    return result;
 }
 
 list_t *reverse_list(list_t *list) {
-    if (!list) {
+    if (list == NULL) {
         return NULL;
     }
 
-    list_t *reversedResult = new_list(list->length, NULL);
-
-    if (!reversedResult) {
+    list_t *reversedList = (list_t *)malloc(sizeof(list_t) + list->length * sizeof(list_element_t));
+    if (reversedList == NULL) {
         return NULL;
     }
 
-    for (size_t i = list->length; i > 0; --i) {
-        reversedResult->elements[list->length - i] = list->elements[i - 1];
+    reversedList->length = list->length;
+
+    for (size_t i = 0; i < list->length; ++i) {
+        reversedList->elements[i] = list->elements[list->length - i - 1];
     }
 
-    return reversedResult;
+    return reversedList;
 }
 
 void delete_list(list_t *list) {