chore: some cleanup

array_list.h

@@ -44,6 +44,15 @@ void alist_add(array_list *alist, ELEMENT_TYPE entry) {
     alist->data[alist->length++] = entry;
 }
 
+void alist_remove(array_list *alist, int index) {
+#ifdef ARRAY_LIST_UNORDERED
+    alist->data[index] = alist->data[--alist->length];
+#else
+    memcpy(&alist->data[index], &alist->data[index + 1], sizeof(ELEMENT_TYPE) * (alist->capacity - index - 1));
+    alist->length--;
+#endif //ARRAY_LIST_UNORDERED
+}
+
 void alist_free(array_list *alist) {
     free(alist->data);
     free(alist);