diff --git a/cv4/list-ops/.docs/instructions.md b/cv4/list-ops/.docs/instructions.md
deleted file mode 100644
index ccfc2f8..0000000
--- a/cv4/list-ops/.docs/instructions.md
+++ /dev/null
@@ -1,19 +0,0 @@
-# Instructions
-
-Implement basic list operations.
-
-In functional languages list operations like `length`, `map`, and `reduce` are very common.
-Implement a series of basic list operations, without using existing functions.
-
-The precise number and names of the operations to be implemented will be track dependent to avoid conflicts with existing names, but the general operations you will implement include:
-
-- `append` (*given two lists, add all items in the second list to the end of the first list*);
-- `concatenate` (*given a series of lists, combine all items in all lists into one flattened list*);
-- `filter` (*given a predicate and a list, return the list of all items for which `predicate(item)` is True*);
-- `length` (*given a list, return the total number of items within it*);
-- `map` (*given a function and a list, return the list of the results of applying `function(item)` on all items*);
-- `foldl` (*given a function, a list, and initial accumulator, fold (reduce) each item into the accumulator from the left*);
-- `foldr` (*given a function, a list, and an initial accumulator, fold (reduce) each item into the accumulator from the right*);
-- `reverse` (*given a list, return a list with all the original items, but in reversed order*).
-
-Note, the ordering in which arguments are passed to the fold functions (`foldl`, `foldr`) is significant.
diff --git a/cv4/list-ops/.meta/config.json b/cv4/list-ops/.meta/config.json
deleted file mode 100644
index dd36a7a..0000000
--- a/cv4/list-ops/.meta/config.json
+++ /dev/null
@@ -1,25 +0,0 @@
-{
-  "authors": [
-    "wolf99"
-  ],
-  "contributors": [
-    "patricksjackson",
-    "rootbeersoup",
-    "ryanplusplus",
-    "xihh87"
-  ],
-  "files": {
-    "solution": [
-      "list_ops.c",
-      "list_ops.h"
-    ],
-    "test": [
-      "test_list_ops.c"
-    ],
-    "example": [
-      ".meta/example.c",
-      ".meta/example.h"
-    ]
-  },
-  "blurb": "Implement basic list operations."
-}
diff --git a/cv4/list-ops/.meta/example.c b/cv4/list-ops/.meta/example.c
deleted file mode 100644
index f2b9e79..0000000
--- a/cv4/list-ops/.meta/example.c
+++ /dev/null
@@ -1,134 +0,0 @@
-#include "list_ops.h"
-#include <string.h>
-
-list_t *new_list(size_t length, list_element_t elements[])
-{
-   list_t *list = malloc(sizeof(*list) + sizeof(list_element_t) * length);
-
-   if (!list)
-      return NULL;
-
-   list->length = length;
-   memcpy(list->elements, elements, sizeof(list_element_t) * length);
-
-   return list;
-}
-
-list_t *append_list(list_t *list1, list_t *list2)
-{
-   if (!list1 || !list2)
-      return NULL;
-
-   size_t length = list1->length + list2->length;
-   list_t *list = malloc(sizeof(*list) + sizeof(list_element_t) * (length));
-
-   if (!list)
-      return NULL;
-
-   list->length = length;
-   if (length) {
-      memcpy(list->elements, list1->elements,
-             sizeof(list_element_t) * list1->length);
-      memcpy(&(list->elements[list1->length]), list2->elements,
-             sizeof(list_element_t) * list2->length);
-   }
-
-   return list;
-}
-
-list_t *filter_list(list_t *list, bool (*filter)(list_element_t))
-{
-   if (!list || !filter)
-      return NULL;
-
-   list_t *filtered =
-       malloc(sizeof(*list) + sizeof(list_element_t) * list->length);
-
-   if (!filtered)
-      return NULL;
-
-   size_t j = 0;
-   for (size_t i = 0; i < list->length && j < list->length; ++i) {
-      if (filter(list->elements[i]))
-         filtered->elements[j++] = list->elements[i];
-   }
-   filtered->length = j;
-
-   return filtered;
-}
-
-size_t length_list(list_t *list)
-{
-   if (!list)
-      return 0;
-   return list->length;
-}
-
-list_t *map_list(list_t *list, list_element_t (*map)(list_element_t))
-{
-   if (!list || !map)
-      return NULL;
-
-   list_t *mapped =
-       malloc(sizeof(*list) + sizeof(list_element_t) * list->length);
-
-   if (!mapped)
-      return NULL;
-
-   mapped->length = list->length;
-   for (size_t i = 0; i < mapped->length; ++i)
-      mapped->elements[i] = map(list->elements[i]);
-
-   return mapped;
-}
-
-list_element_t foldl_list(list_t *list, list_element_t initial,
-                          list_element_t (*foldl)(list_element_t,
-                                                  list_element_t))
-{
-   if (!list || !foldl)
-      return 0;
-
-   for (size_t i = 0; i < list->length; ++i)
-      initial = foldl(list->elements[i], initial);
-
-   return initial;
-}
-
-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)
-      return 0;
-
-   for (size_t i = list->length; i > 0; --i)
-      initial = foldr(list->elements[i - 1], initial);
-
-   return initial;
-}
-
-list_t *reverse_list(list_t *list)
-{
-   if (!list)
-      return NULL;
-
-   list_t *reversed =
-       malloc(sizeof(*list) + sizeof(list_element_t) * list->length);
-
-   if (!reversed)
-      return NULL;
-
-   reversed->length = list->length;
-   for (size_t i = 0, j = reversed->length - 1; i < reversed->length;
-        i++, j--) {
-      reversed->elements[i] = list->elements[j];
-   }
-
-   return reversed;
-}
-
-void delete_list(list_t *list)
-{
-   free(list);
-}
diff --git a/cv4/list-ops/.meta/example.h b/cv4/list-ops/.meta/example.h
deleted file mode 100644
index 14a56d8..0000000
--- a/cv4/list-ops/.meta/example.h
+++ /dev/null
@@ -1,47 +0,0 @@
-#ifndef LIST_OPS_H
-#define LIST_OPS_H
-
-#include <stdlib.h>
-#include <stdbool.h>
-
-typedef int list_element_t;
-
-typedef struct {
-   size_t length;
-   list_element_t elements[];
-} list_t;
-
-// constructs a new list
-list_t *new_list(size_t length, list_element_t elements[]);
-
-// append entries to a list and return the new list
-list_t *append_list(list_t *list1, list_t *list2);
-
-// filter list returning only values that satisfy the filter function
-list_t *filter_list(list_t *list, bool (*filter)(list_element_t));
-
-// returns the length of the list
-size_t length_list(list_t *list);
-
-// return a list of elements whose values equal the list value transformed by
-// the mapping function
-list_t *map_list(list_t *list, list_element_t (*map)(list_element_t));
-
-// folds (reduces) the given list from the left with a function
-list_element_t foldl_list(list_t *list, list_element_t initial,
-                          list_element_t (*foldl)(list_element_t,
-                                                  list_element_t));
-
-// folds (reduces) the given list from the right with a function
-list_element_t foldr_list(list_t *list, list_element_t initial,
-                          list_element_t (*foldr)(list_element_t,
-                                                  list_element_t));
-
-// reverse the elements of the list
-list_t *reverse_list(list_t *list);
-
-// destroy the entire list
-// list will be a dangling pointer after calling this method on it
-void delete_list(list_t *list);
-
-#endif
diff --git a/cv4/list-ops/.meta/tests.toml b/cv4/list-ops/.meta/tests.toml
deleted file mode 100644
index b182853..0000000
--- a/cv4/list-ops/.meta/tests.toml
+++ /dev/null
@@ -1,105 +0,0 @@
-# This is an auto-generated file. Regular comments will be removed when this
-# file is regenerated. Regenerating will not touch any manually added keys,
-# so comments can be added in a "comment" key.
-
-[485b9452-bf94-40f7-a3db-c3cf4850066a]
-description = "empty lists"
-
-[2c894696-b609-4569-b149-8672134d340a]
-description = "list to empty list"
-
-[e842efed-3bf6-4295-b371-4d67a4fdf19c]
-description = "empty list to list"
-
-[71dcf5eb-73ae-4a0e-b744-a52ee387922f]
-description = "non-empty lists"
-
-[28444355-201b-4af2-a2f6-5550227bde21]
-description = "empty list"
-include = false
-
-[331451c1-9573-42a1-9869-2d06e3b389a9]
-description = "list of lists"
-include = false
-comment = "C does not easily allow a single implementation for multiple types (Liskov substitution)"
-
-[d6ecd72c-197f-40c3-89a4-aa1f45827e09]
-description = "list of nested lists"
-include = false
-comment = "C does not easily allow a single implementation for multiple types (Liskov substitution)"
-
-[0524fba8-3e0f-4531-ad2b-f7a43da86a16]
-description = "empty list"
-
-[88494bd5-f520-4edb-8631-88e415b62d24]
-description = "non-empty list"
-
-[1cf0b92d-8d96-41d5-9c21-7b3c37cb6aad]
-description = "empty list"
-
-[d7b8d2d9-2d16-44c4-9a19-6e5f237cb71e]
-description = "non-empty list"
-
-[c0bc8962-30e2-4bec-9ae4-668b8ecd75aa]
-description = "empty list"
-
-[11e71a95-e78b-4909-b8e4-60cdcaec0e91]
-description = "non-empty list"
-
-[613b20b7-1873-4070-a3a6-70ae5f50d7cc]
-description = "empty list"
-include = false
-
-[e56df3eb-9405-416a-b13a-aabb4c3b5194]
-description = "direction independent function applied to non-empty list"
-include = false
-coment = "reimplemented"
-
-[d2cf5644-aee1-4dfc-9b88-06896676fe27]
-description = "direction dependent function applied to non-empty list"
-
-[36549237-f765-4a4c-bfd9-5d3a8f7b07d2]
-description = "empty list"
-
-[7a626a3c-03ec-42bc-9840-53f280e13067]
-description = "direction independent function applied to non-empty list"
-
-[d7fcad99-e88e-40e1-a539-4c519681f390]
-description = "direction dependent function applied to non-empty list"
-include = false
-comment = "Prefer integer division test case (d2cf5644-aee1-4dfc-9b88-06896676fe27)"
-
-[aeb576b9-118e-4a57-a451-db49fac20fdc]
-description = "empty list"
-include = false
-coment = "reimplemented"
-
-[c4b64e58-313e-4c47-9c68-7764964efb8e]
-description = "direction independent function applied to non-empty list"
-include = false
-coment = "reimplemented"
-
-[be396a53-c074-4db3-8dd6-f7ed003cce7c]
-description = "direction dependent function applied to non-empty list"
-
-[17214edb-20ba-42fc-bda8-000a5ab525b0]
-description = "empty list"
-
-[e1c64db7-9253-4a3d-a7c4-5273b9e2a1bd]
-description = "direction independent function applied to non-empty list"
-
-[8066003b-f2ff-437e-9103-66e6df474844]
-description = "direction dependent function applied to non-empty list"
-include = false
-comment = "Prefer integer division test case (be396a53-c074-4db3-8dd6-f7ed003cce7c)"
-
-[94231515-050e-4841-943d-d4488ab4ee30]
-description = "empty list"
-
-[fcc03d1e-42e0-4712-b689-d54ad761f360]
-description = "non-empty list"
-
-[40872990-b5b8-4cb8-9085-d91fc0d05d26]
-description = "list of lists is not flattened"
-include = false
-comment = "C does not easily allow a single implementation for multiple types (Liskov substitution)"
diff --git a/cv4/list-ops/.zip b/cv4/list-ops/.zip
deleted file mode 100644
index a6a1489..0000000
Binary files a/cv4/list-ops/.zip and /dev/null differ
diff --git a/cv4/list_ops.c b/cv4/list_ops.c
index a488be1..4bf4a64 100644
--- a/cv4/list_ops.c
+++ b/cv4/list_ops.c
@@ -39,11 +39,30 @@ list_t *append_list(list_t *list1, list_t *list2) {
 }
 
 // filter list returning only values that satisfy the filter function
-list_t *filter_list(list_t *list, bool (*filter)(list_element_t)){
-  return NULL;
+list_t *filter_list(list_t *list, bool (*filter)(list_element_t)) {
+    if (list == NULL) return NULL;
+    
+    size_t filteredLength = 0;
+    for (size_t i = 0; i < list->length; ++i) {
+        if (filter(list->elements[i])) {
+            ++filteredLength;
+        }
+    }
 
+    list_t *filtered = malloc(sizeof(list_t) + filteredLength * sizeof(list_element_t));
+    if (filtered != NULL) {
+        filtered->length = filteredLength;
+        size_t j = 0;
+        for (size_t i = 0; i < list->length; ++i) {
+            if (filter(list->elements[i])) {
+                filtered->elements[j++] = list->elements[i];
+            }
+        }
+    }
+    return filtered;
 }
 
+
 // returns the length of the list
 size_t length_list(list_t *list) {
     return (list != NULL) ? list->length : 0;
@@ -64,28 +83,47 @@ list_t *map_list(list_t *list, list_element_t (*map)(list_element_t)) {
 }
 
 // folds (reduces) the given list from the left with a function
-list_element_t foldl_list(list_t *list, list_element_t initial, list_element_t (*foldl)(list_element_t, list_element_t)){
-  list_element_t accumulator = initial;
-  
-  return res;
-
+list_element_t foldl_list(list_t *list, list_element_t initial,
+                          list_element_t (*foldl)(list_element_t, list_element_t)) {
+    list_element_t accumulator = initial;
+    if (list != NULL) {
+        for (size_t i = 0; i < list->length; ++i) {
+            accumulator = foldl(list->elements[i], accumulator);
+        }
+    }
+    return accumulator;
 }
 
 // folds (reduces) the given list from the right with a function
-list_element_t foldr_list(list_t *list, list_element_t initial,list_element_t (*foldr)(list_element_t, list_element_t)){
-  list_element_t res=0;
-  return res;
-
+list_element_t foldr_list(list_t *list, list_element_t initial,
+                          list_element_t (*foldr)(list_element_t, list_element_t)) {
+    list_element_t accumulator = initial;
+    if (list != NULL) {
+        for (size_t i = list->length; i > 0; --i) {
+            accumulator = foldr(list->elements[i - 1], accumulator);
+        }
+    }
+    return accumulator;
 }
 
 // reverse the elements of the list
-list_t *reverse_list(list_t *list){
-  return NULL;
-
+list_t *reverse_list(list_t *list) {
+    if (list == NULL) return NULL;
+    
+    list_t *reversedList = new_list(list->length, list->elements);
+    if (reversedList != NULL) {
+        for (size_t i = 0; i < list->length / 2; ++i) {
+            list_element_t temp = reversedList->elements[i];
+            reversedList->elements[i] = reversedList->elements[list->length - i - 1];
+            reversedList->elements[list->length - i - 1] = temp;
+        }
+    }
+    return reversedList;
 }
 
+
 // destroy the entire list
 // list will be a dangling pointer after calling this method on it
-void delete_list(list_t *list){
-
-} 
\ No newline at end of file
+void delete_list(list_t *list) {
+    free(list);
+}