Sync tests for practice exercise list-ops

exercises/practice/list-ops/.meta/config.json

@@ -17,6 +17,7 @@
     "msomji",
     "muzimuzhi",
     "RonakLakhotia",
+    "sanderploegsma",
     "SleeplessByte",
     "Smarticles101",
     "sshine",

exercises/practice/list-ops/.meta/src/reference/java/ListOps.java

@@ -1,9 +1,8 @@
-
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.List;
-import java.util.function.*;
-import java.util.stream.Collectors;
+import java.util.function.BiFunction;
+import java.util.function.Function;
+import java.util.function.Predicate;
 
 class ListOps {
 
@@ -21,47 +20,53 @@ static <T> List<T> concat(final List<List<T>> listOfLists) {
     }
 
     static <T> List<T> filter(final List<T> list, Predicate<T> predicate) {
-        return list.stream().filter(predicate).collect(Collectors.toList());
+        final List<T> result = new ArrayList<>();
+        for (T item : list) {
+            if (predicate.test(item)) {
+                result.add(item);
+            }
+        }
+        return result;
     }
 
     static <T> int size(final List<T> list) {
         return list.size();
     }
 
     static <T, U> List<U> map(final List<T> list, Function<T, U> transform) {
-        return list.stream().map(transform).collect(Collectors.toList());
+        final List<U> result = new ArrayList<>();
+        for (T item : list) {
+            result.add(transform.apply(item));
+        }
+        return result;
     }
 
     static <T> List<T> reverse(final List<T> list) {
-        final List<T> result = new ArrayList<>(list);
-        Collections.reverse(result);
+        final List<T> result = new ArrayList<>();
+        for (int i = list.size() - 1; i >= 0; i--) {
+            result.add(list.get(i));
+        }
         return result;
     }
 
     static <T, U> U foldLeft(final List<T> list, final U initial, final BiFunction<U, T, U> f) {
-        if (list.isEmpty()) {
-            return initial;
+        U acc = initial;
+
+        for (T item : list) {
+            acc = f.apply(acc, item);
         }
 
-        return foldLeft(
-                new ArrayList<>(list.subList(1, list.size())),
-                f.apply(
-                        initial,
-                        list.get(0)),
-                f);
+        return acc;
     }
 
     static <T, U> U foldRight(final List<T> list, final U initial, final BiFunction<T, U, U> f) {
-        if (list.isEmpty()) {
-            return initial;
+        U acc = initial;
+
+        for (int i = list.size() - 1; i >= 0; i--) {
+            acc = f.apply(list.get(i), acc);
         }
 
-        return f.apply(
-                list.get(0),
-                foldRight(
-                        new ArrayList<>(list.subList(1, list.size())),
-                        initial,
-                        f));
+        return acc;
     }
 
     private ListOps() {

exercises/practice/list-ops/.meta/tests.toml

@@ -1,66 +1,106 @@
-# 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.
+# This is an auto-generated file.
+#
+# Regenerating this file via `configlet sync` will:
+# - Recreate every `description` key/value pair
+# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
+# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
+# - Preserve any other key/value pair
+#
+# As user-added comments (using the # character) will be removed when this file
+# is regenerated, comments can be added via a `comment` key.
 
 [485b9452-bf94-40f7-a3db-c3cf4850066a]
-description = "empty lists"
+description = "append entries to a list and return the new list -> empty lists"
 
 [2c894696-b609-4569-b149-8672134d340a]
-description = "list to empty list"
+description = "append entries to a list and return the new list -> list to empty list"
+
+[e842efed-3bf6-4295-b371-4d67a4fdf19c]
+description = "append entries to a list and return the new list -> empty list to list"
 
 [71dcf5eb-73ae-4a0e-b744-a52ee387922f]
-description = "non-empty lists"
+description = "append entries to a list and return the new list -> non-empty lists"
 
 [28444355-201b-4af2-a2f6-5550227bde21]
-description = "empty list"
+description = "concatenate a list of lists -> empty list"
 
 [331451c1-9573-42a1-9869-2d06e3b389a9]
-description = "list of lists"
+description = "concatenate a list of lists -> list of lists"
 
 [d6ecd72c-197f-40c3-89a4-aa1f45827e09]
-description = "list of nested lists"
+description = "concatenate a list of lists -> list of nested lists"
 
 [0524fba8-3e0f-4531-ad2b-f7a43da86a16]
-description = "empty list"
+description = "filter list returning only values that satisfy the filter function -> empty list"
 
 [88494bd5-f520-4edb-8631-88e415b62d24]
-description = "non-empty list"
+description = "filter list returning only values that satisfy the filter function -> non-empty list"
 
 [1cf0b92d-8d96-41d5-9c21-7b3c37cb6aad]
-description = "empty list"
+description = "returns the length of a list -> empty list"
 
 [d7b8d2d9-2d16-44c4-9a19-6e5f237cb71e]
-description = "non-empty list"
+description = "returns the length of a list -> non-empty list"
 
 [c0bc8962-30e2-4bec-9ae4-668b8ecd75aa]
-description = "empty list"
+description = "return a list of elements whose values equal the list value transformed by the mapping function -> empty list"
 
 [11e71a95-e78b-4909-b8e4-60cdcaec0e91]
-description = "non-empty list"
+description = "return a list of elements whose values equal the list value transformed by the mapping function -> non-empty list"
 
 [613b20b7-1873-4070-a3a6-70ae5f50d7cc]
-description = "empty list"
+description = "folds (reduces) the given list from the left with a function -> empty list"
+include = false
 
 [e56df3eb-9405-416a-b13a-aabb4c3b5194]
-description = "direction independent function applied to non-empty list"
+description = "folds (reduces) the given list from the left with a function -> direction independent function applied to non-empty list"
+include = false
 
 [d2cf5644-aee1-4dfc-9b88-06896676fe27]
-description = "direction dependent function applied to non-empty list"
+description = "folds (reduces) the given list from the left with a function -> direction dependent function applied to non-empty list"
+include = false
+
+[36549237-f765-4a4c-bfd9-5d3a8f7b07d2]
+description = "folds (reduces) the given list from the left with a function -> empty list"
+reimplements = "613b20b7-1873-4070-a3a6-70ae5f50d7cc"
+
+[7a626a3c-03ec-42bc-9840-53f280e13067]
+description = "folds (reduces) the given list from the left with a function -> direction independent function applied to non-empty list"
+reimplements = "e56df3eb-9405-416a-b13a-aabb4c3b5194"
+
+[d7fcad99-e88e-40e1-a539-4c519681f390]
+description = "folds (reduces) the given list from the left with a function -> direction dependent function applied to non-empty list"
+reimplements = "d2cf5644-aee1-4dfc-9b88-06896676fe27"
 
 [aeb576b9-118e-4a57-a451-db49fac20fdc]
-description = "empty list"
+description = "folds (reduces) the given list from the right with a function -> empty list"
+include = false
 
 [c4b64e58-313e-4c47-9c68-7764964efb8e]
-description = "direction independent function applied to non-empty list"
+description = "folds (reduces) the given list from the right with a function -> direction independent function applied to non-empty list"
+include = false
 
 [be396a53-c074-4db3-8dd6-f7ed003cce7c]
-description = "direction dependent function applied to non-empty list"
+description = "folds (reduces) the given list from the right with a function -> direction dependent function applied to non-empty list"
+include = false
+
+[17214edb-20ba-42fc-bda8-000a5ab525b0]
+description = "folds (reduces) the given list from the right with a function -> empty list"
+reimplements = "aeb576b9-118e-4a57-a451-db49fac20fdc"
+
+[e1c64db7-9253-4a3d-a7c4-5273b9e2a1bd]
+description = "folds (reduces) the given list from the right with a function -> direction independent function applied to non-empty list"
+reimplements = "c4b64e58-313e-4c47-9c68-7764964efb8e"
+
+[8066003b-f2ff-437e-9103-66e6df474844]
+description = "folds (reduces) the given list from the right with a function -> direction dependent function applied to non-empty list"
+reimplements = "be396a53-c074-4db3-8dd6-f7ed003cce7c"
 
 [94231515-050e-4841-943d-d4488ab4ee30]
-description = "empty list"
+description = "reverse the elements of the list -> empty list"
 
 [fcc03d1e-42e0-4712-b689-d54ad761f360]
-description = "non-empty list"
+description = "reverse the elements of the list -> non-empty list"
 
 [40872990-b5b8-4cb8-9085-d91fc0d05d26]
-description = "list of lists is not flattened"
+description = "reverse the elements of the list -> list of lists is not flattened"