Refactor to simplify and make more readable

Author: WillGibson

list_things/src/continuous_subset.py

@@ -4,22 +4,18 @@
 
 def continuous_subset_adding_up_to(full_set: list[int], target_sum: int) -> Optional[list[int]]:
     accumulated_sums = list(accumulate(full_set))
-
     slice_length = 1
     list_length = len(full_set)
+
     while slice_length <= list_length:
         left_index = 0
+        right_index = slice_length - 1
         while left_index <= list_length - slice_length:
-            right_index = left_index + slice_length - 1
-            if left_index == 0:
-                if accumulated_sums[right_index] == target_sum:
-                    return full_set[left_index:slice_length]
-            elif accumulated_sums[right_index] - accumulated_sums[left_index - 1] == target_sum:
-                if slice_length == 1:
-                    return [full_set[right_index]]
-                else:
-                    return full_set[left_index : left_index + slice_length]
+            to_subtract = 0 if left_index == 0 else accumulated_sums[left_index - 1]
+            if accumulated_sums[right_index] - to_subtract == target_sum:
+                return full_set[left_index : left_index + slice_length]
             left_index += 1
+            right_index += 1
         slice_length += 1
 
     # Not able to find a subset adding up to target

list_things/tests/test_continuous_subset.py

@@ -13,6 +13,7 @@ def test_sublist_with_unnattainable_target_returns_none(self):
             ([1], 1, [1]),
             ([1, 2, 3, 4], 1, [1]),
             ([1, 2, 3, 4], 3, [3]),
+            ([1, 2, 4, 5], 3, [1, 2]),
             ([1, 2, 3, 4], 6, [1, 2, 3]),
             ([1, 2, 3, 4], 10, [1, 2, 3, 4]),
             ([1, 2, 3, 4], 9, [2, 3, 4]),
@@ -31,9 +32,9 @@ def test_returns_subset_adding_up_to_target_sum(self, full_set, target_sum, expe
             (1000, 13076),
             (10000, 130476),
             (100000, 1500090),
-            (1000000, 1500090),  # Takes about 350ms
-            (10000000, 1500090),  # Takes about 642ms
-            (10000000, 97000900),  # Takes about 30s
+            (1000000, 1500090),  # Takes about 325ms
+            (10000000, 1500090),  # Takes about 600ms
+            # (10000000, 97000900),  # Takes about 30s
         ],
     )
     def test_works_with_larger_lists(self, list_size, target_sum):