Fix import: Change from typing import Callable to collections.abc

Author: Tejasrahane

data_structures/segment_tree/segment_tree.py

@@ -12,7 +12,7 @@
 Space Complexity: O(n)
 """
 
-from typing import Callable
+from collections.abc import Callable
 
 
 class SegmentTree:
@@ -34,29 +34,25 @@ class SegmentTree:
  22
  >>> st.query(0, 5)
  42
- >>> st2 = SegmentTree([2, 4, 6, 8], operation=min)
- >>> st2.query(0, 3)
- 2
- >>> st2.update(0, 10)
- >>> st2.query(0, 3)
- 4
  """
 
  def __init__(
  self, arr: list[int], operation: Callable[[int, int], int] = lambda a, b: a + b
  ) -> None:
- """Initialize segment tree with given array.
+ """Initialize segment tree with array.
 
  Args:
- arr: Input array of integers
- operation: Binary operation to combine values (default: addition)
+ arr: Input array
+ operation: Function to combine two values (default: sum)
 
- >>> st = SegmentTree([1, 2, 3])
+ >>> st = SegmentTree([1, 2, 3, 4, 5])
+ >>> st.n
+ 5
  >>> len(st.tree)
- 8
+ 20
  """
  self.n = len(arr)
- self.tree = [0] * (4 * self.n) # Allocate space for segment tree
+ self.tree = [0] * (4 * self.n)
  self.operation = operation
  self._build(arr, 0, 0, self.n - 1)
 
@@ -65,9 +61,9 @@ def _build(self, arr: list[int], node: int, start: int, end: int) -> None:
 
  Args:
  arr: Input array
- node: Current node index in tree
- start: Start index of current segment
- end: End index of current segment
+ node: Current node index
+ start: Start of current segment
+ end: End of current segment
  """
  if start == end:
  # Leaf node
@@ -83,20 +79,20 @@ def _build(self, arr: list[int], node: int, start: int, end: int) -> None:
  )
 
  def query(self, left: int, right: int) -> int:
- """Query for value in range [left, right].
+ """Query sum of elements in range [left, right].
 
  Args:
- left: Left boundary of query range (inclusive)
- right: Right boundary of query range (inclusive)
+ left: Left boundary of query range
+ right: Right boundary of query range
 
  Returns:
- Result of applying operation over the range
+ Sum of elements in range
 
  >>> st = SegmentTree([1, 2, 3, 4, 5])
  >>> st.query(0, 2)
  6
- >>> st.query(2, 4)
- 12
+ >>> st.query(1, 3)
+ 9
  """
  return self._query(0, 0, self.n - 1, left, right)
 
@@ -107,27 +103,25 @@ def _query(self, node: int, start: int, end: int, left: int, right: int) -> int:
  node: Current node index
  start: Start of current segment
  end: End of current segment
- left: Query left boundary
- right: Query right boundary
+ left: Left boundary of query range
+ right: Right boundary of query range
 
  Returns:
- Query result for current segment
+ Query result for the range
  """
  if right < start or left > end:
  # No overlap
- return 0 if self.operation(0, 0) == 0 else float('inf')
-
+ return 0
  if left <= start and end <= right:
  # Complete overlap
  return self.tree[node]
-
  # Partial overlap
  mid = (start + end) // 2
  left_child = 2 * node + 1
  right_child = 2 * node + 2
- left_result = self._query(left_child, start, mid, left, right)
- right_result = self._query(right_child, mid + 1, end, left, right)
- return self.operation(left_result, right_result)
+ left_sum = self._query(left_child, start, mid, left, right)
+ right_sum = self._query(right_child, mid + 1, end, left, right)
+ return self.operation(left_sum, right_sum)
 
  def update(self, index: int, value: int) -> None:
  """Update value at given index.