Add doctests to interpolation_search.py (TheAlgorithms#11492)

* Add doctests to interpolation_search.py * update docs * update tests * update tests 2 * clean code

Author: Ihor-Pryyma

searches/interpolation_search.py

@@ -3,13 +3,41 @@
 """
 
 
-def interpolation_search(sorted_collection, item):
- """Pure implementation of interpolation search algorithm in Python
- Be careful collection must be ascending sorted, otherwise result will be
- unpredictable
- :param sorted_collection: some ascending sorted collection with comparable items
- :param item: item value to search
- :return: index of found item or None if item is not found
+def interpolation_search(sorted_collection: list[int], item: int) -> int | None:
+ """
+ Searches for an item in a sorted collection by interpolation search algorithm.
+
+ Args:
+ sorted_collection: sorted list of integers
+ item: item value to search
+
+ Returns:
+ int: The index of the found item, or None if the item is not found.
+ Examples:
+ >>> interpolation_search([1, 2, 3, 4, 5], 2)
+ 1
+ >>> interpolation_search([1, 2, 3, 4, 5], 4)
+ 3
+ >>> interpolation_search([1, 2, 3, 4, 5], 6) is None
+ True
+ >>> interpolation_search([], 1) is None
+ True
+ >>> interpolation_search([100], 100)
+ 0
+ >>> interpolation_search([1, 2, 3, 4, 5], 0) is None
+ True
+ >>> interpolation_search([1, 2, 3, 4, 5], 7) is None
+ True
+ >>> interpolation_search([1, 2, 3, 4, 5], 2)
+ 1
+ >>> interpolation_search([1, 2, 3, 4, 5], 0) is None
+ True
+ >>> interpolation_search([1, 2, 3, 4, 5], 7) is None
+ True
+ >>> interpolation_search([1, 2, 3, 4, 5], 2)
+ 1
+ >>> interpolation_search([5, 5, 5, 5, 5], 3) is None
+ True
  """
  left = 0
  right = len(sorted_collection) - 1
@@ -19,8 +47,7 @@ def interpolation_search(sorted_collection, item):
  if sorted_collection[left] == sorted_collection[right]:
  if sorted_collection[left] == item:
  return left
- else:
- return None
+ return None
 
  point = left + ((item - sorted_collection[left]) * (right - left)) // (
  sorted_collection[right] - sorted_collection[left]
@@ -33,7 +60,7 @@ def interpolation_search(sorted_collection, item):
  current_item = sorted_collection[point]
  if current_item == item:
  return point
- elif point < left:
+ if point < left:
  right = left
  left = point
  elif point > right:
@@ -46,22 +73,42 @@ def interpolation_search(sorted_collection, item):
  return None
 
 
-def interpolation_search_by_recursion(sorted_collection, item, left, right):
+def interpolation_search_by_recursion(
+ sorted_collection: list[int], item: int, left: int = 0, right: int | None = None
+) -> int | None:
  """Pure implementation of interpolation search algorithm in Python by recursion
  Be careful collection must be ascending sorted, otherwise result will be
  unpredictable
  First recursion should be started with left=0 and right=(len(sorted_collection)-1)
- :param sorted_collection: some ascending sorted collection with comparable items
- :param item: item value to search
- :return: index of found item or None if item is not found
- """
 
+ Args:
+ sorted_collection: some sorted collection with comparable items
+ item: item value to search
+ left: left index in collection
+ right: right index in collection
+
+ Returns:
+ index of item in collection or None if item is not present
+
+ Examples:
+ >>> interpolation_search_by_recursion([0, 5, 7, 10, 15], 0)
+ 0
+ >>> interpolation_search_by_recursion([0, 5, 7, 10, 15], 15)
+ 4
+ >>> interpolation_search_by_recursion([0, 5, 7, 10, 15], 5)
+ 1
+ >>> interpolation_search_by_recursion([0, 5, 7, 10, 15], 100) is None
+ True
+ >>> interpolation_search_by_recursion([5, 5, 5, 5, 5], 3) is None
+ True
+ """
+ if right is None:
+ right = len(sorted_collection) - 1
  # avoid divided by 0 during interpolation
  if sorted_collection[left] == sorted_collection[right]:
  if sorted_collection[left] == item:
  return left
- else:
- return None
+ return None
 
  point = left + ((item - sorted_collection[left]) * (right - left)) // (
  sorted_collection[right] - sorted_collection[left]
@@ -73,64 +120,18 @@ def interpolation_search_by_recursion(sorted_collection, item, left, right):
 
  if sorted_collection[point] == item:
  return point
- elif point < left:
+ if point < left:
  return interpolation_search_by_recursion(sorted_collection, item, point, left)
- elif point > right:
+ if point > right:
  return interpolation_search_by_recursion(sorted_collection, item, right, left)
- elif sorted_collection[point] > item:
+ if sorted_collection[point] > item:
  return interpolation_search_by_recursion(
  sorted_collection, item, left, point - 1
  )
- else:
- return interpolation_search_by_recursion(
- sorted_collection, item, point + 1, right
- )
-
-
-def __assert_sorted(collection):
- """Check if collection is ascending sorted, if not - raises :py:class:`ValueError`
- :param collection: collection
- :return: True if collection is ascending sorted
- :raise: :py:class:`ValueError` if collection is not ascending sorted
- Examples:
- >>> __assert_sorted([0, 1, 2, 4])
- True
- >>> __assert_sorted([10, -1, 5])
- Traceback (most recent call last):
- ...
- ValueError: Collection must be ascending sorted
- """
- if collection != sorted(collection):
- raise ValueError("Collection must be ascending sorted")
- return True
+ return interpolation_search_by_recursion(sorted_collection, item, point + 1, right)
 
 
 if __name__ == "__main__":
- import sys
+ import doctest
 
- """
- user_input = input('Enter numbers separated by comma:\n').strip()
- collection = [int(item) for item in user_input.split(',')]
- try:
- __assert_sorted(collection)
- except ValueError:
- sys.exit('Sequence must be ascending sorted to apply interpolation search')
-
- target_input = input('Enter a single number to be found in the list:\n')
- target = int(target_input)
- """
-
- debug = 0
- if debug == 1:
- collection = [10, 30, 40, 45, 50, 66, 77, 93]
- try:
- __assert_sorted(collection)
- except ValueError:
- sys.exit("Sequence must be ascending sorted to apply interpolation search")
- target = 67
-
- result = interpolation_search(collection, target)
- if result is not None:
- print(f"{target} found at positions: {result}")
- else:
- print("Not found")
+ doctest.testmod()