From 0457860ed491521b02d1559a76874d3e766823c0 Mon Sep 17 00:00:00 2001
From: Putul Singh <127419636+putul03@users.noreply.github.com>
Date: Sat, 19 Oct 2024 13:21:16 +0530
Subject: [PATCH 01/16] Suffix Array and LCP Array Implementation

---
 divide_and_conquer/suffix_array_lcp.py | 62 ++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)
 create mode 100644 divide_and_conquer/suffix_array_lcp.py

diff --git a/divide_and_conquer/suffix_array_lcp.py b/divide_and_conquer/suffix_array_lcp.py
new file mode 100644
index 000000000000..c78acf49cdac
--- /dev/null
+++ b/divide_and_conquer/suffix_array_lcp.py
@@ -0,0 +1,62 @@
+#!/usr/bin/env python3
+
+def build_suffix_array(s: str) -> list[int]:
+    """
+    Build the suffix array for the given string.
+
+    Parameters:
+        s (str): The input string.
+
+    Returns:
+        list[int]: The suffix array (a list of starting indices of
+                    suffixes in sorted order).
+    """
+    suffixes = [(s[i:], i) for i in range(len(s))]
+    suffixes.sort()  # Sort the suffixes lexicographically
+    suffix_array = [suffix[1] for suffix in suffixes]
+    return suffix_array
+
+def build_lcp_array(s: str, suffix_array: list[int]) -> list[int]:
+    """
+    Build the LCP array for the given string and suffix array.
+
+    Parameters:
+        s (str): The input string.
+        suffix_array (list[int]): The suffix array.
+
+    Returns:
+        list[int]: The LCP array.
+    """
+    n = len(s)
+    rank = [0] * n
+    lcp = [0] * n
+
+    # Compute the rank of each suffix
+    for i, suffix_index in enumerate(suffix_array):
+        rank[suffix_index] = i
+
+    # Compute the LCP array
+    h = 0
+    for i in range(n):
+        if rank[i] > 0:
+            j = suffix_array[rank[i] - 1]
+            while (i + h < n) and (j + h < n) and (s[i + h] == s[j + h]):
+                h += 1
+            lcp[rank[i]] = h
+            if h > 0:
+                h -= 1  # Decrease h for the next suffix
+    return lcp
+
+# Example usage
+if __name__ == "__main__":
+    s = "banana"
+    suffix_array = build_suffix_array(s)
+    lcp_array = build_lcp_array(s, suffix_array)
+
+    print("Suffix Array:")
+    for i in range(len(suffix_array)):
+        print(f"{suffix_array[i]}: {s[suffix_array[i]:]}")
+
+    print("\nLCP Array:")
+    for i in range(1, len(lcp_array)):
+        print(f"LCP between {s[suffix_array[i - 1]:]} and {s[suffix_array[i]]}: {lcp_array[i]}")

From 465cea3cbb59fcde7fb54550d44570b37b1bd174 Mon Sep 17 00:00:00 2001
From: Putul Singh <127419636+putul03@users.noreply.github.com>
Date: Sat, 19 Oct 2024 15:55:36 +0530
Subject: [PATCH 02/16] Delete divide_and_conquer/suffix_array_lcp.py

---
 divide_and_conquer/suffix_array_lcp.py | 62 --------------------------
 1 file changed, 62 deletions(-)
 delete mode 100644 divide_and_conquer/suffix_array_lcp.py

diff --git a/divide_and_conquer/suffix_array_lcp.py b/divide_and_conquer/suffix_array_lcp.py
deleted file mode 100644
index c78acf49cdac..000000000000
--- a/divide_and_conquer/suffix_array_lcp.py
+++ /dev/null
@@ -1,62 +0,0 @@
-#!/usr/bin/env python3
-
-def build_suffix_array(s: str) -> list[int]:
-    """
-    Build the suffix array for the given string.
-
-    Parameters:
-        s (str): The input string.
-
-    Returns:
-        list[int]: The suffix array (a list of starting indices of
-                    suffixes in sorted order).
-    """
-    suffixes = [(s[i:], i) for i in range(len(s))]
-    suffixes.sort()  # Sort the suffixes lexicographically
-    suffix_array = [suffix[1] for suffix in suffixes]
-    return suffix_array
-
-def build_lcp_array(s: str, suffix_array: list[int]) -> list[int]:
-    """
-    Build the LCP array for the given string and suffix array.
-
-    Parameters:
-        s (str): The input string.
-        suffix_array (list[int]): The suffix array.
-
-    Returns:
-        list[int]: The LCP array.
-    """
-    n = len(s)
-    rank = [0] * n
-    lcp = [0] * n
-
-    # Compute the rank of each suffix
-    for i, suffix_index in enumerate(suffix_array):
-        rank[suffix_index] = i
-
-    # Compute the LCP array
-    h = 0
-    for i in range(n):
-        if rank[i] > 0:
-            j = suffix_array[rank[i] - 1]
-            while (i + h < n) and (j + h < n) and (s[i + h] == s[j + h]):
-                h += 1
-            lcp[rank[i]] = h
-            if h > 0:
-                h -= 1  # Decrease h for the next suffix
-    return lcp
-
-# Example usage
-if __name__ == "__main__":
-    s = "banana"
-    suffix_array = build_suffix_array(s)
-    lcp_array = build_lcp_array(s, suffix_array)
-
-    print("Suffix Array:")
-    for i in range(len(suffix_array)):
-        print(f"{suffix_array[i]}: {s[suffix_array[i]:]}")
-
-    print("\nLCP Array:")
-    for i in range(1, len(lcp_array)):
-        print(f"LCP between {s[suffix_array[i - 1]:]} and {s[suffix_array[i]]}: {lcp_array[i]}")

From 8ab292751c50cf330e9253402d335006304d43e0 Mon Sep 17 00:00:00 2001
From: Putul Singh <127419636+putul03@users.noreply.github.com>
Date: Sat, 19 Oct 2024 15:58:29 +0530
Subject: [PATCH 03/16] Add files via upload

---
 data_structures/persistent_segment_tree.py | 80 ++++++++++++++++++++++
 1 file changed, 80 insertions(+)
 create mode 100644 data_structures/persistent_segment_tree.py

diff --git a/data_structures/persistent_segment_tree.py b/data_structures/persistent_segment_tree.py
new file mode 100644
index 000000000000..8963b54a2ba6
--- /dev/null
+++ b/data_structures/persistent_segment_tree.py
@@ -0,0 +1,80 @@
+class Node:
+    def __init__(self, value: int = 0) -> None:
+        self.value = value
+        self.left = None
+        self.right = None
+
+
+class PersistentSegmentTree:
+    def __init__(self, arr: list[int]) -> None:
+        self.n = len(arr)
+        self.roots: list[Node] = []
+        self.roots.append(self._build(arr, 0, self.n - 1))
+
+    def _build(self, arr: list[int], start: int, end: int) -> Node:
+        """
+        Builds a segment tree from the provided array.
+
+        >>> pst = PersistentSegmentTree([1, 2, 3])
+        >>> root = pst._build([1, 2, 3], 0, 2)
+        >>> root.value  # Sum of the whole array
+        6
+        """
+        if start == end:
+            return Node(arr[start])
+        mid = (start + end) // 2
+        node = Node()
+        node.left = self._build(arr, start, mid)
+        node.right = self._build(arr, mid + 1, end)
+        node.value = node.left.value + node.right.value
+        return node
+
+    def update(self, version: int, index: int, value: int) -> int:
+        """
+        Updates the segment tree with a new value at the specified index.
+
+        >>> pst = PersistentSegmentTree([1, 2, 3])
+        >>> version_1 = pst.update(0, 1, 5)
+        >>> pst.query(version_1, 0, 2)  # Query sum from index 0 to 2
+        9
+        """
+        new_root = self._update(self.roots[version], 0, self.n - 1, index, value)
+        self.roots.append(new_root)
+        return len(self.roots) - 1  # return the index of the new version
+
+    def _update(self, node: Node, start: int, end: int, index: int, value: int) -> Node:
+        if start == end:
+            new_node = Node(value)
+            return new_node
+        mid = (start + end) // 2
+        new_node = Node()
+        if index <= mid:
+            new_node.left = self._update(node.left, start, mid, index, value)
+            new_node.right = node.right
+        else:
+            new_node.left = node.left
+            new_node.right = self._update(node.right, mid + 1, end, index, value)
+        new_node.value = new_node.left.value + new_node.right.value
+        return new_node
+
+    def query(self, version: int, left: int, right: int) -> int:
+        """
+        Queries the sum in the given range for the specified version.
+
+        >>> pst = PersistentSegmentTree([1, 2, 3])
+        >>> version_1 = pst.update(0, 1, 5)
+        >>> pst.query(version_1, 0, 1)  # Query sum from index 0 to 1
+        6
+        >>> pst.query(version_1, 0, 2)  # Query sum from index 0 to 2
+        9
+        """
+        return self._query(self.roots[version], 0, self.n - 1, left, right)
+
+    def _query(self, node: Node, start: int, end: int, left: int, right: int) -> int:
+        if left > end or right < start:
+            return 0
+        if left <= start and right >= end:
+            return node.value
+        mid = (start + end) // 2
+        return (self._query(node.left, start, mid, left, right) +
+                self._query(node.right, mid + 1, end, left, right))

From f5d380aafb63f7f676ff00dfd651ba3c691daac0 Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Sat, 19 Oct 2024 10:30:45 +0000
Subject: [PATCH 04/16] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 data_structures/persistent_segment_tree.py | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/data_structures/persistent_segment_tree.py b/data_structures/persistent_segment_tree.py
index 8963b54a2ba6..7d7851071612 100644
--- a/data_structures/persistent_segment_tree.py
+++ b/data_structures/persistent_segment_tree.py
@@ -76,5 +76,6 @@ def _query(self, node: Node, start: int, end: int, left: int, right: int) -> int
         if left <= start and right >= end:
             return node.value
         mid = (start + end) // 2
-        return (self._query(node.left, start, mid, left, right) +
-                self._query(node.right, mid + 1, end, left, right))
+        return self._query(node.left, start, mid, left, right) + self._query(
+            node.right, mid + 1, end, left, right
+        )

From 819fdc88360a83d6d451c1ac501db54a9f6208b3 Mon Sep 17 00:00:00 2001
From: Putul Singh <127419636+putul03@users.noreply.github.com>
Date: Sat, 19 Oct 2024 16:16:21 +0530
Subject: [PATCH 05/16] Update persistent_segment_tree.py

---
 data_structures/persistent_segment_tree.py | 48 +++++++++++++---------
 1 file changed, 29 insertions(+), 19 deletions(-)

diff --git a/data_structures/persistent_segment_tree.py b/data_structures/persistent_segment_tree.py
index 7d7851071612..5bcf1f64d80e 100644
--- a/data_structures/persistent_segment_tree.py
+++ b/data_structures/persistent_segment_tree.py
@@ -7,19 +7,18 @@ def __init__(self, value: int = 0) -> None:
 
 class PersistentSegmentTree:
     def __init__(self, arr: list[int]) -> None:
-        self.n = len(arr)
-        self.roots: list[Node] = []
-        self.roots.append(self._build(arr, 0, self.n - 1))
-
-    def _build(self, arr: list[int], start: int, end: int) -> Node:
         """
-        Builds a segment tree from the provided array.
+        Initialize the Persistent Segment Tree with the given array.
 
         >>> pst = PersistentSegmentTree([1, 2, 3])
-        >>> root = pst._build([1, 2, 3], 0, 2)
-        >>> root.value  # Sum of the whole array
+        >>> pst.query(0, 0, 2)
         6
         """
+        self.n = len(arr)
+        self.roots: list[Node] = []
+        self.roots.append(self._build(arr, 0, self.n - 1))
+
+    def _build(self, arr: list[int], start: int, end: int) -> Node:
         if start == end:
             return Node(arr[start])
         mid = (start + end) // 2
@@ -31,41 +30,46 @@ def _build(self, arr: list[int], start: int, end: int) -> Node:
 
     def update(self, version: int, index: int, value: int) -> int:
         """
-        Updates the segment tree with a new value at the specified index.
+        Update the value at the given index and return the new version.
 
         >>> pst = PersistentSegmentTree([1, 2, 3])
         >>> version_1 = pst.update(0, 1, 5)
-        >>> pst.query(version_1, 0, 2)  # Query sum from index 0 to 2
+        >>> pst.query(version_1, 0, 2)
         9
         """
         new_root = self._update(self.roots[version], 0, self.n - 1, index, value)
         self.roots.append(new_root)
-        return len(self.roots) - 1  # return the index of the new version
+        return len(self.roots) - 1
 
     def _update(self, node: Node, start: int, end: int, index: int, value: int) -> Node:
         if start == end:
-            new_node = Node(value)
-            return new_node
+            return Node(value)
+
         mid = (start + end) // 2
         new_node = Node()
+
         if index <= mid:
             new_node.left = self._update(node.left, start, mid, index, value)
             new_node.right = node.right
         else:
             new_node.left = node.left
             new_node.right = self._update(node.right, mid + 1, end, index, value)
+
         new_node.value = new_node.left.value + new_node.right.value
+
         return new_node
 
     def query(self, version: int, left: int, right: int) -> int:
         """
-        Queries the sum in the given range for the specified version.
+        Query the sum in the given range for the specified version.
 
         >>> pst = PersistentSegmentTree([1, 2, 3])
+        >>> pst.query(0, 0, 2)
+        6
         >>> version_1 = pst.update(0, 1, 5)
-        >>> pst.query(version_1, 0, 1)  # Query sum from index 0 to 1
+        >>> pst.query(version_1, 0, 1)
         6
-        >>> pst.query(version_1, 0, 2)  # Query sum from index 0 to 2
+        >>> pst.query(version_1, 0, 2)
         9
         """
         return self._query(self.roots[version], 0, self.n - 1, left, right)
@@ -76,6 +80,12 @@ def _query(self, node: Node, start: int, end: int, left: int, right: int) -> int
         if left <= start and right >= end:
             return node.value
         mid = (start + end) // 2
-        return self._query(node.left, start, mid, left, right) + self._query(
-            node.right, mid + 1, end, left, right
-        )
+        return (self._query(node.left, start, mid, left, right) +
+                self._query(node.right, mid + 1, end, left, right))
+
+
+if __name__ == "__main__":
+    import doctest
+    print("Running doctests...")
+    result = doctest.testmod()
+    print(f"Ran {result.attempted} tests, {result.failed} failed.")

From 5de61840107d734cdc44b3b11602dbc53e41e7b5 Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Sat, 19 Oct 2024 10:47:29 +0000
Subject: [PATCH 06/16] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 data_structures/persistent_segment_tree.py | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/data_structures/persistent_segment_tree.py b/data_structures/persistent_segment_tree.py
index 5bcf1f64d80e..24a44d90a4b3 100644
--- a/data_structures/persistent_segment_tree.py
+++ b/data_structures/persistent_segment_tree.py
@@ -80,12 +80,14 @@ def _query(self, node: Node, start: int, end: int, left: int, right: int) -> int
         if left <= start and right >= end:
             return node.value
         mid = (start + end) // 2
-        return (self._query(node.left, start, mid, left, right) +
-                self._query(node.right, mid + 1, end, left, right))
+        return self._query(node.left, start, mid, left, right) + self._query(
+            node.right, mid + 1, end, left, right
+        )
 
 
 if __name__ == "__main__":
     import doctest
+
     print("Running doctests...")
     result = doctest.testmod()
     print(f"Ran {result.attempted} tests, {result.failed} failed.")

From 82270b7c636b42533099f7ac4069590c752a71ee Mon Sep 17 00:00:00 2001
From: Putul Singh <127419636+putul03@users.noreply.github.com>
Date: Sat, 19 Oct 2024 16:19:23 +0530
Subject: [PATCH 07/16] Update persistent_segment_tree.py

---
 data_structures/persistent_segment_tree.py | 73 +++++++++++++---------
 1 file changed, 42 insertions(+), 31 deletions(-)

diff --git a/data_structures/persistent_segment_tree.py b/data_structures/persistent_segment_tree.py
index 24a44d90a4b3..bc65603480c5 100644
--- a/data_structures/persistent_segment_tree.py
+++ b/data_structures/persistent_segment_tree.py
@@ -7,18 +7,23 @@ def __init__(self, value: int = 0) -> None:
 
 class PersistentSegmentTree:
     def __init__(self, arr: list[int]) -> None:
-        """
-        Initialize the Persistent Segment Tree with the given array.
-
-        >>> pst = PersistentSegmentTree([1, 2, 3])
-        >>> pst.query(0, 0, 2)
-        6
-        """
         self.n = len(arr)
         self.roots: list[Node] = []
         self.roots.append(self._build(arr, 0, self.n - 1))
 
     def _build(self, arr: list[int], start: int, end: int) -> Node:
+        """
+        Builds a segment tree from the provided array.
+
+        >>> pst = PersistentSegmentTree([1, 2, 3, 4])
+        >>> root = pst._build([1, 2, 3, 4], 0, 3)
+        >>> root.value  # Sum of the whole array
+        10
+        >>> root.left.value  # Sum of the left half
+        3
+        >>> root.right.value  # Sum of the right half
+        7
+        """
         if start == end:
             return Node(arr[start])
         mid = (start + end) // 2
@@ -29,19 +34,26 @@ def _build(self, arr: list[int], start: int, end: int) -> Node:
         return node
 
     def update(self, version: int, index: int, value: int) -> int:
-        """
-        Update the value at the given index and return the new version.
-
-        >>> pst = PersistentSegmentTree([1, 2, 3])
-        >>> version_1 = pst.update(0, 1, 5)
-        >>> pst.query(version_1, 0, 2)
-        9
-        """
         new_root = self._update(self.roots[version], 0, self.n - 1, index, value)
         self.roots.append(new_root)
         return len(self.roots) - 1
 
     def _update(self, node: Node, start: int, end: int, index: int, value: int) -> Node:
+        """
+        Updates the node for the specified index and value and returns the new node.
+
+        >>> pst = PersistentSegmentTree([1, 2, 3, 4])
+        >>> old_root = pst.roots[0]
+        >>> new_root = pst._update(old_root, 0, 3, 1, 5)  # Update index 1 to 5
+        >>> new_root.value  # New sum after update
+        13
+        >>> old_root.value  # Old root remains unchanged
+        10
+        >>> new_root.left.value  # Updated left child
+        6
+        >>> new_root.right.value  # Right child remains the same
+        7
+        """
         if start == end:
             return Node(value)
 
@@ -60,34 +72,33 @@ def _update(self, node: Node, start: int, end: int, index: int, value: int) -> N
         return new_node
 
     def query(self, version: int, left: int, right: int) -> int:
-        """
-        Query the sum in the given range for the specified version.
-
-        >>> pst = PersistentSegmentTree([1, 2, 3])
-        >>> pst.query(0, 0, 2)
-        6
-        >>> version_1 = pst.update(0, 1, 5)
-        >>> pst.query(version_1, 0, 1)
-        6
-        >>> pst.query(version_1, 0, 2)
-        9
-        """
         return self._query(self.roots[version], 0, self.n - 1, left, right)
 
     def _query(self, node: Node, start: int, end: int, left: int, right: int) -> int:
+        """
+        Queries the sum of values in the range [left, right] for the given node.
+
+        >>> pst = PersistentSegmentTree([1, 2, 3, 4])
+        >>> root = pst.roots[0]
+        >>> pst._query(root, 0, 3, 1, 2)  # Sum of elements at index 1 and 2
+        5
+        >>> pst._query(root, 0, 3, 0, 3)  # Sum of all elements
+        10
+        >>> pst._query(root, 0, 3, 2, 3)  # Sum of elements at index 2 and 3
+        7
+        """
         if left > end or right < start:
             return 0
         if left <= start and right >= end:
             return node.value
         mid = (start + end) // 2
-        return self._query(node.left, start, mid, left, right) + self._query(
-            node.right, mid + 1, end, left, right
-        )
+        return (self._query(node.left, start, mid, left, right) +
+                self._query(node.right, mid + 1, end, left, right))
 
 
+# Running the doctests
 if __name__ == "__main__":
     import doctest
-
     print("Running doctests...")
     result = doctest.testmod()
     print(f"Ran {result.attempted} tests, {result.failed} failed.")

From ff5a9b81c4620701b1264f6c4d9875833588dfe7 Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Sat, 19 Oct 2024 10:50:37 +0000
Subject: [PATCH 08/16] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 data_structures/persistent_segment_tree.py | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/data_structures/persistent_segment_tree.py b/data_structures/persistent_segment_tree.py
index bc65603480c5..32f1ec0df0a7 100644
--- a/data_structures/persistent_segment_tree.py
+++ b/data_structures/persistent_segment_tree.py
@@ -92,13 +92,15 @@ def _query(self, node: Node, start: int, end: int, left: int, right: int) -> int
         if left <= start and right >= end:
             return node.value
         mid = (start + end) // 2
-        return (self._query(node.left, start, mid, left, right) +
-                self._query(node.right, mid + 1, end, left, right))
+        return self._query(node.left, start, mid, left, right) + self._query(
+            node.right, mid + 1, end, left, right
+        )
 
 
 # Running the doctests
 if __name__ == "__main__":
     import doctest
+
     print("Running doctests...")
     result = doctest.testmod()
     print(f"Ran {result.attempted} tests, {result.failed} failed.")

From 04b44c4c7b78aabf2acad2e59d4a64c405ded94b Mon Sep 17 00:00:00 2001
From: Putul Singh <127419636+putul03@users.noreply.github.com>
Date: Sat, 19 Oct 2024 16:22:59 +0530
Subject: [PATCH 09/16] Update persistent_segment_tree.py

---
 data_structures/persistent_segment_tree.py | 33 +++++++++++++++++++---
 1 file changed, 29 insertions(+), 4 deletions(-)

diff --git a/data_structures/persistent_segment_tree.py b/data_structures/persistent_segment_tree.py
index 32f1ec0df0a7..b0bc7ed3faa4 100644
--- a/data_structures/persistent_segment_tree.py
+++ b/data_structures/persistent_segment_tree.py
@@ -34,6 +34,19 @@ def _build(self, arr: list[int], start: int, end: int) -> Node:
         return node
 
     def update(self, version: int, index: int, value: int) -> int:
+        """
+        Updates the value at the given index and returns the new version.
+
+        >>> pst = PersistentSegmentTree([1, 2, 3, 4])
+        >>> version_1 = pst.update(0, 1, 5)  # Update index 1 to 5
+        >>> pst.query(version_1, 0, 3)  # Query sum of all elements in new version
+        13
+        >>> pst.query(0, 0, 3)  # Original version remains unchanged
+        10
+        >>> version_2 = pst.update(version_1, 3, 6)  # Update index 3 to 6 in version_1
+        >>> pst.query(version_2, 0, 3)  # Query sum of all elements in newest version
+        15
+        """
         new_root = self._update(self.roots[version], 0, self.n - 1, index, value)
         self.roots.append(new_root)
         return len(self.roots) - 1
@@ -72,6 +85,20 @@ def _update(self, node: Node, start: int, end: int, index: int, value: int) -> N
         return new_node
 
     def query(self, version: int, left: int, right: int) -> int:
+        """
+        Queries the sum in the given range for the specified version.
+
+        >>> pst = PersistentSegmentTree([1, 2, 3, 4])
+        >>> pst.query(0, 0, 3)  # Sum of all elements in original version
+        10
+        >>> pst.query(0, 1, 2)  # Sum of elements at index 1 and 2 in original version
+        5
+        >>> version_1 = pst.update(0, 1, 5)  # Update index 1 to 5
+        >>> pst.query(version_1, 0, 3)  # Sum of all elements in new version
+        13
+        >>> pst.query(version_1, 1, 2)  # Sum of elements at index 1 and 2 in new version
+        8
+        """
         return self._query(self.roots[version], 0, self.n - 1, left, right)
 
     def _query(self, node: Node, start: int, end: int, left: int, right: int) -> int:
@@ -92,15 +119,13 @@ def _query(self, node: Node, start: int, end: int, left: int, right: int) -> int
         if left <= start and right >= end:
             return node.value
         mid = (start + end) // 2
-        return self._query(node.left, start, mid, left, right) + self._query(
-            node.right, mid + 1, end, left, right
-        )
+        return (self._query(node.left, start, mid, left, right) +
+                self._query(node.right, mid + 1, end, left, right))
 
 
 # Running the doctests
 if __name__ == "__main__":
     import doctest
-
     print("Running doctests...")
     result = doctest.testmod()
     print(f"Ran {result.attempted} tests, {result.failed} failed.")

From 0f5718fa688a17a0917841d14111adabc3fe149d Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Sat, 19 Oct 2024 10:54:28 +0000
Subject: [PATCH 10/16] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 data_structures/persistent_segment_tree.py | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/data_structures/persistent_segment_tree.py b/data_structures/persistent_segment_tree.py
index b0bc7ed3faa4..884075437416 100644
--- a/data_structures/persistent_segment_tree.py
+++ b/data_structures/persistent_segment_tree.py
@@ -119,13 +119,15 @@ def _query(self, node: Node, start: int, end: int, left: int, right: int) -> int
         if left <= start and right >= end:
             return node.value
         mid = (start + end) // 2
-        return (self._query(node.left, start, mid, left, right) +
-                self._query(node.right, mid + 1, end, left, right))
+        return self._query(node.left, start, mid, left, right) + self._query(
+            node.right, mid + 1, end, left, right
+        )
 
 
 # Running the doctests
 if __name__ == "__main__":
     import doctest
+
     print("Running doctests...")
     result = doctest.testmod()
     print(f"Ran {result.attempted} tests, {result.failed} failed.")

From eb9e2b73c6bd31ce4cc9f6233b23c3cddd16bf18 Mon Sep 17 00:00:00 2001
From: Putul Singh <127419636+putul03@users.noreply.github.com>
Date: Sat, 19 Oct 2024 16:27:52 +0530
Subject: [PATCH 11/16] Update persistent_segment_tree.py

---
 data_structures/persistent_segment_tree.py | 24 ++++++++++------------
 1 file changed, 11 insertions(+), 13 deletions(-)

diff --git a/data_structures/persistent_segment_tree.py b/data_structures/persistent_segment_tree.py
index 884075437416..e3a8427917fe 100644
--- a/data_structures/persistent_segment_tree.py
+++ b/data_structures/persistent_segment_tree.py
@@ -1,17 +1,18 @@
+from typing import List, Optional
+
 class Node:
     def __init__(self, value: int = 0) -> None:
-        self.value = value
-        self.left = None
-        self.right = None
-
+        self.value: int = value
+        self.left: Optional[Node] = None
+        self.right: Optional[Node] = None
 
 class PersistentSegmentTree:
-    def __init__(self, arr: list[int]) -> None:
-        self.n = len(arr)
-        self.roots: list[Node] = []
+    def __init__(self, arr: List[int]) -> None:
+        self.n: int = len(arr)
+        self.roots: List[Node] = []
         self.roots.append(self._build(arr, 0, self.n - 1))
 
-    def _build(self, arr: list[int], start: int, end: int) -> Node:
+    def _build(self, arr: List[int], start: int, end: int) -> Node:
         """
         Builds a segment tree from the provided array.
 
@@ -119,15 +120,12 @@ def _query(self, node: Node, start: int, end: int, left: int, right: int) -> int
         if left <= start and right >= end:
             return node.value
         mid = (start + end) // 2
-        return self._query(node.left, start, mid, left, right) + self._query(
-            node.right, mid + 1, end, left, right
-        )
-
+        return (self._query(node.left, start, mid, left, right) +
+                self._query(node.right, mid + 1, end, left, right))
 
 # Running the doctests
 if __name__ == "__main__":
     import doctest
-
     print("Running doctests...")
     result = doctest.testmod()
     print(f"Ran {result.attempted} tests, {result.failed} failed.")

From 5c605df8b239599ba70df7a25291381e945ab38b Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Sat, 19 Oct 2024 10:58:52 +0000
Subject: [PATCH 12/16] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 data_structures/persistent_segment_tree.py | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/data_structures/persistent_segment_tree.py b/data_structures/persistent_segment_tree.py
index e3a8427917fe..f7d0bdbbc87f 100644
--- a/data_structures/persistent_segment_tree.py
+++ b/data_structures/persistent_segment_tree.py
@@ -1,11 +1,13 @@
 from typing import List, Optional
 
+
 class Node:
     def __init__(self, value: int = 0) -> None:
         self.value: int = value
         self.left: Optional[Node] = None
         self.right: Optional[Node] = None
 
+
 class PersistentSegmentTree:
     def __init__(self, arr: List[int]) -> None:
         self.n: int = len(arr)
@@ -120,12 +122,15 @@ def _query(self, node: Node, start: int, end: int, left: int, right: int) -> int
         if left <= start and right >= end:
             return node.value
         mid = (start + end) // 2
-        return (self._query(node.left, start, mid, left, right) +
-                self._query(node.right, mid + 1, end, left, right))
+        return self._query(node.left, start, mid, left, right) + self._query(
+            node.right, mid + 1, end, left, right
+        )
+
 
 # Running the doctests
 if __name__ == "__main__":
     import doctest
+
     print("Running doctests...")
     result = doctest.testmod()
     print(f"Ran {result.attempted} tests, {result.failed} failed.")

From 55e6a87625f10ca2abd8cc4460ae7fa0bd1ed228 Mon Sep 17 00:00:00 2001
From: Putul Singh <127419636+putul03@users.noreply.github.com>
Date: Sat, 19 Oct 2024 16:43:40 +0530
Subject: [PATCH 13/16] Update persistent_segment_tree.py

---
 data_structures/persistent_segment_tree.py | 24 +++++++++-------------
 1 file changed, 10 insertions(+), 14 deletions(-)

diff --git a/data_structures/persistent_segment_tree.py b/data_structures/persistent_segment_tree.py
index f7d0bdbbc87f..4b1670819955 100644
--- a/data_structures/persistent_segment_tree.py
+++ b/data_structures/persistent_segment_tree.py
@@ -1,20 +1,18 @@
-from typing import List, Optional
-
+from __future__ import annotations
 
 class Node:
     def __init__(self, value: int = 0) -> None:
         self.value: int = value
-        self.left: Optional[Node] = None
-        self.right: Optional[Node] = None
-
+        self.left: Node | None = None
+        self.right: Node | None = None
 
 class PersistentSegmentTree:
-    def __init__(self, arr: List[int]) -> None:
+    def __init__(self, arr: list[int]) -> None:
         self.n: int = len(arr)
-        self.roots: List[Node] = []
+        self.roots: list[Node] = []
         self.roots.append(self._build(arr, 0, self.n - 1))
 
-    def _build(self, arr: List[int], start: int, end: int) -> Node:
+    def _build(self, arr: list[int], start: int, end: int) -> Node:
         """
         Builds a segment tree from the provided array.
 
@@ -83,7 +81,8 @@ def _update(self, node: Node, start: int, end: int, index: int, value: int) -> N
             new_node.left = node.left
             new_node.right = self._update(node.right, mid + 1, end, index, value)
 
-        new_node.value = new_node.left.value + new_node.right.value
+        new_node.value = (new_node.left.value if new_node.left else 0) + \
+                         (new_node.right.value if new_node.right else 0)
 
         return new_node
 
@@ -122,15 +121,12 @@ def _query(self, node: Node, start: int, end: int, left: int, right: int) -> int
         if left <= start and right >= end:
             return node.value
         mid = (start + end) // 2
-        return self._query(node.left, start, mid, left, right) + self._query(
-            node.right, mid + 1, end, left, right
-        )
-
+        return (self._query(node.left, start, mid, left, right) +
+                self._query(node.right, mid + 1, end, left, right))
 
 # Running the doctests
 if __name__ == "__main__":
     import doctest
-
     print("Running doctests...")
     result = doctest.testmod()
     print(f"Ran {result.attempted} tests, {result.failed} failed.")

From eaafd1ca3c99f6e97b8fc6026c470d81c4e7d023 Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Sat, 19 Oct 2024 11:14:53 +0000
Subject: [PATCH 14/16] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 data_structures/persistent_segment_tree.py | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/data_structures/persistent_segment_tree.py b/data_structures/persistent_segment_tree.py
index 4b1670819955..e153deff5ef4 100644
--- a/data_structures/persistent_segment_tree.py
+++ b/data_structures/persistent_segment_tree.py
@@ -1,11 +1,13 @@
 from __future__ import annotations
 
+
 class Node:
     def __init__(self, value: int = 0) -> None:
         self.value: int = value
         self.left: Node | None = None
         self.right: Node | None = None
 
+
 class PersistentSegmentTree:
     def __init__(self, arr: list[int]) -> None:
         self.n: int = len(arr)
@@ -81,8 +83,9 @@ def _update(self, node: Node, start: int, end: int, index: int, value: int) -> N
             new_node.left = node.left
             new_node.right = self._update(node.right, mid + 1, end, index, value)
 
-        new_node.value = (new_node.left.value if new_node.left else 0) + \
-                         (new_node.right.value if new_node.right else 0)
+        new_node.value = (new_node.left.value if new_node.left else 0) + (
+            new_node.right.value if new_node.right else 0
+        )
 
         return new_node
 
@@ -121,12 +124,15 @@ def _query(self, node: Node, start: int, end: int, left: int, right: int) -> int
         if left <= start and right >= end:
             return node.value
         mid = (start + end) // 2
-        return (self._query(node.left, start, mid, left, right) +
-                self._query(node.right, mid + 1, end, left, right))
+        return self._query(node.left, start, mid, left, right) + self._query(
+            node.right, mid + 1, end, left, right
+        )
+
 
 # Running the doctests
 if __name__ == "__main__":
     import doctest
+
     print("Running doctests...")
     result = doctest.testmod()
     print(f"Ran {result.attempted} tests, {result.failed} failed.")

From 124b177795957b010560b10f497c8a627ab28f47 Mon Sep 17 00:00:00 2001
From: Putul Singh <127419636+putul03@users.noreply.github.com>
Date: Sat, 19 Oct 2024 16:49:21 +0530
Subject: [PATCH 15/16] Update persistent_segment_tree.py

---
 data_structures/persistent_segment_tree.py | 21 +++++++--------------
 1 file changed, 7 insertions(+), 14 deletions(-)

diff --git a/data_structures/persistent_segment_tree.py b/data_structures/persistent_segment_tree.py
index e153deff5ef4..074e137bb366 100644
--- a/data_structures/persistent_segment_tree.py
+++ b/data_structures/persistent_segment_tree.py
@@ -1,13 +1,11 @@
 from __future__ import annotations
 
-
 class Node:
     def __init__(self, value: int = 0) -> None:
         self.value: int = value
         self.left: Node | None = None
         self.right: Node | None = None
 
-
 class PersistentSegmentTree:
     def __init__(self, arr: list[int]) -> None:
         self.n: int = len(arr)
@@ -78,14 +76,12 @@ def _update(self, node: Node, start: int, end: int, index: int, value: int) -> N
 
         if index <= mid:
             new_node.left = self._update(node.left, start, mid, index, value)
-            new_node.right = node.right
+            new_node.right = node.right  # Ensure right node is the same as the original
         else:
-            new_node.left = node.left
+            new_node.left = node.left  # Ensure left node is the same as the original
             new_node.right = self._update(node.right, mid + 1, end, index, value)
 
-        new_node.value = (new_node.left.value if new_node.left else 0) + (
-            new_node.right.value if new_node.right else 0
-        )
+        new_node.value = new_node.left.value + (new_node.right.value if new_node.right else 0)
 
         return new_node
 
@@ -101,7 +97,7 @@ def query(self, version: int, left: int, right: int) -> int:
         >>> version_1 = pst.update(0, 1, 5)  # Update index 1 to 5
         >>> pst.query(version_1, 0, 3)  # Sum of all elements in new version
         13
-        >>> pst.query(version_1, 1, 2)  # Sum of elements at index 1 and 2 in new version
+        >>> pst.query(version_1, 1, 2)  # Sum of elements at index 1 and 2 
         8
         """
         return self._query(self.roots[version], 0, self.n - 1, left, right)
@@ -119,20 +115,17 @@ def _query(self, node: Node, start: int, end: int, left: int, right: int) -> int
         >>> pst._query(root, 0, 3, 2, 3)  # Sum of elements at index 2 and 3
         7
         """
-        if left > end or right < start:
+        if node is None or left > end or right < start:
             return 0
         if left <= start and right >= end:
             return node.value
         mid = (start + end) // 2
-        return self._query(node.left, start, mid, left, right) + self._query(
-            node.right, mid + 1, end, left, right
-        )
-
+        return (self._query(node.left, start, mid, left, right) +
+                self._query(node.right, mid + 1, end, left, right))
 
 # Running the doctests
 if __name__ == "__main__":
     import doctest
-
     print("Running doctests...")
     result = doctest.testmod()
     print(f"Ran {result.attempted} tests, {result.failed} failed.")

From 902ed932ad9969889cbc15953253c2ad6e979d72 Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Sat, 19 Oct 2024 11:20:24 +0000
Subject: [PATCH 16/16] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 data_structures/persistent_segment_tree.py | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/data_structures/persistent_segment_tree.py b/data_structures/persistent_segment_tree.py
index 074e137bb366..05194fa20a4a 100644
--- a/data_structures/persistent_segment_tree.py
+++ b/data_structures/persistent_segment_tree.py
@@ -1,11 +1,13 @@
 from __future__ import annotations
 
+
 class Node:
     def __init__(self, value: int = 0) -> None:
         self.value: int = value
         self.left: Node | None = None
         self.right: Node | None = None
 
+
 class PersistentSegmentTree:
     def __init__(self, arr: list[int]) -> None:
         self.n: int = len(arr)
@@ -81,7 +83,9 @@ def _update(self, node: Node, start: int, end: int, index: int, value: int) -> N
             new_node.left = node.left  # Ensure left node is the same as the original
             new_node.right = self._update(node.right, mid + 1, end, index, value)
 
-        new_node.value = new_node.left.value + (new_node.right.value if new_node.right else 0)
+        new_node.value = new_node.left.value + (
+            new_node.right.value if new_node.right else 0
+        )
 
         return new_node
 
@@ -97,7 +101,7 @@ def query(self, version: int, left: int, right: int) -> int:
         >>> version_1 = pst.update(0, 1, 5)  # Update index 1 to 5
         >>> pst.query(version_1, 0, 3)  # Sum of all elements in new version
         13
-        >>> pst.query(version_1, 1, 2)  # Sum of elements at index 1 and 2 
+        >>> pst.query(version_1, 1, 2)  # Sum of elements at index 1 and 2
         8
         """
         return self._query(self.roots[version], 0, self.n - 1, left, right)
@@ -120,12 +124,15 @@ def _query(self, node: Node, start: int, end: int, left: int, right: int) -> int
         if left <= start and right >= end:
             return node.value
         mid = (start + end) // 2
-        return (self._query(node.left, start, mid, left, right) +
-                self._query(node.right, mid + 1, end, left, right))
+        return self._query(node.left, start, mid, left, right) + self._query(
+            node.right, mid + 1, end, left, right
+        )
+
 
 # Running the doctests
 if __name__ == "__main__":
     import doctest
+
     print("Running doctests...")
     result = doctest.testmod()
     print(f"Ran {result.attempted} tests, {result.failed} failed.")