task: Add type hints to inversions.py

data_structures/hashing/hash_table_with_linked_list.py

@@ -8,7 +8,7 @@ def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
 
     def _set_value(self, key, data):
-        self.values[key] = deque([]) if self.values[key] is None else self.values[key]
+        self.values[key] = deque() if self.values[key] is None else self.values[key]
         self.values[key].appendleft(data)
         self._keys[key] = self.values[key]
 

divide_and_conquer/inversions.py

@@ -9,7 +9,7 @@
 """
 
 
-def count_inversions_bf(arr):
+def count_inversions_bf(arr: list[int]) -> int:
     """
     Counts the number of inversions using a naive brute-force algorithm
     Parameters
@@ -40,7 +40,7 @@ def count_inversions_bf(arr):
     return num_inversions
 
 
-def count_inversions_recursive(arr):
+def count_inversions_recursive(arr: list[int]) -> tuple[list[int], int]:
     """
     Counts the number of inversions using a divide-and-conquer algorithm
     Parameters
@@ -74,7 +74,7 @@ def count_inversions_recursive(arr):
     return c, num_inversions
 
 
-def _count_cross_inversions(p, q):
+def _count_cross_inversions(p: list[int], q: list[int]) -> tuple[list[int], int]:
     """
     Counts the inversions across two sorted arrays.
     And combine the two arrays into one sorted array
@@ -118,7 +118,7 @@ def _count_cross_inversions(p, q):
     return r, num_inversion
 
 
-def main():
+def main() -> None:
     arr_1 = [10, 2, 1, 5, 5, 2, 11]
 
     # this arr has 8 inversions: