Fix bugs and typo errors in closest_pair_of_points.py

Author: Roy027

divide_and_conquer/closest_pair_of_points.py

@@ -19,24 +19,32 @@
 Time complexity: O(n * log n)
 """
 
+from __future__ import annotations
 
-def euclidean_distance_sqr(point1, point2):
+from typing import Any
+
+
+def euclidean_distance_sqr(
+    point1: list[Any] | tuple[Any, ...], point2: list[Any] | tuple[Any, ...]
+) -> float:
     """
-    >>> euclidean_distance_sqr([1,2],[2,4])
+    >>> euclidean_distance_sqr([1, 2], [2, 4])
     5
     """
     return (point1[0] - point2[0]) ** 2 + (point1[1] - point2[1]) ** 2
 
 
-def column_based_sort(array, column=0):
+def column_based_sort(array: list[Any], column: int = 0) -> list[Any]:
     """
     >>> column_based_sort([(5, 1), (4, 2), (3, 0)], 1)
     [(3, 0), (5, 1), (4, 2)]
     """
     return sorted(array, key=lambda x: x[column])
 
 
-def dis_between_closest_pair(points, points_counts, min_dis=float("inf")):
+def dis_between_closest_pair(
+    points: list[Any], points_counts: int, min_dis: float | None = None
+) -> float:
     """
     brute force approach to find distance between closest pair points
 
@@ -46,10 +54,12 @@ def dis_between_closest_pair(points, points_counts, min_dis=float("inf")):
     Returns :
     min_dis (float):  distance between closest pair of points
 
-    >>> dis_between_closest_pair([[1,2],[2,4],[5,7],[8,9],[11,0]],5)
+    >>> dis_between_closest_pair([[1, 2], [2, 4], [5, 7], [8, 9], [11, 0]], 5)
     5
 
     """
+    if min_dis is None:
+        min_dis = float("inf")
 
     for i in range(points_counts - 1):
         for j in range(i + 1, points_counts):
@@ -58,7 +68,9 @@ def dis_between_closest_pair(points, points_counts, min_dis=float("inf")):
     return min_dis
 
 
-def dis_between_closest_in_strip(points, points_counts, min_dis=float("inf")):
+def dis_between_closest_in_strip(
+    points: list[Any], points_counts: int, min_dis: float | None = None
+) -> float:
     """
     closest pair of points in strip
 
@@ -68,18 +80,22 @@ def dis_between_closest_in_strip(points, points_counts, min_dis=float("inf")):
     Returns :
     min_dis (float):  distance btw closest pair of points in the strip (< min_dis)
 
-    >>> dis_between_closest_in_strip([[1,2],[2,4],[5,7],[8,9],[11,0]],5)
-    85
+    >>> dis_between_closest_in_strip([[1, 2], [2, 4], [5, 7], [8, 9], [11, 0]], 5)
+    5
     """
+    if min_dis is None:
+        min_dis = float("inf")
 
-    for i in range(points_counts-1):
-        for j in range(i+1, min(i + 6, points_counts)):
+    for i in range(points_counts - 1):
+        for j in range(i + 1, min(i + 6, points_counts)):
             current_dis = euclidean_distance_sqr(points[i], points[j])
             min_dis = min(min_dis, current_dis)
     return min_dis
 
 
-def closest_pair_of_points_sqr(points_sorted_on_x, points_sorted_on_y, points_counts):
+def closest_pair_of_points_sqr(
+    points_sorted_on_x: list[Any], points_sorted_on_y: list[Any], points_counts: int
+) -> float:
     """divide and conquer approach
 
     Parameters :
@@ -88,7 +104,7 @@ def closest_pair_of_points_sqr(points_sorted_on_x, points_sorted_on_y, points_co
     Returns :
     (float):  distance btw closest pair of points
 
-    >>> closest_pair_of_points_sqr([(1, 2), (3, 4)], [(5, 6), (7, 8)], 2)
+    >>> closest_pair_of_points_sqr([(1, 2), (3, 4)], [(1, 2), (3, 4)], 2)
     8
     """
 
@@ -122,20 +138,22 @@ def closest_pair_of_points_sqr(points_sorted_on_x, points_sorted_on_y, points_co
     return min(closest_pair_dis, closest_in_strip)
 
 
-def closest_pair_of_points(points, points_counts):
+def closest_pair_of_points(points: list[Any], points_counts: int) -> float:
     """
-    >>> closest_pair_of_points([(2, 3), (12, 30)], len([(2, 3), (12, 30)]))
+    >>> closest_pair_of_points([(2, 3), (12, 30)], 2)
     28.792360097775937
     """
     points_sorted_on_x = column_based_sort(points, column=0)
     points_sorted_on_y = column_based_sort(points, column=1)
     return (
-        closest_pair_of_points_sqr(
-            points_sorted_on_x, points_sorted_on_y, points_counts
-        )
+        closest_pair_of_points_sqr(points_sorted_on_x, points_sorted_on_y, points_counts)
     ) ** 0.5
 
 
 if __name__ == "__main__":
+    import doctest
+
+    doctest.testmod()
+
     points = [(2, 3), (12, 30), (40, 50), (5, 1), (12, 10), (3, 4)]
-    print("Distance:", closest_pair_of_points(points, len(points)))
+    print(f"Distance: {closest_pair_of_points(points, len(points))}")