Added tasks 172-191

Author: ThanhNIT

README.md

@@ -298,6 +298,7 @@ Python-based LeetCode algorithm problem solutions, regularly updated.
 |-|-|-|-|-|-
 | 0108 |[Convert Sorted Array to Binary Search Tree](src/main/python/g0101_0200/s0108_convert_sorted_array_to_binary_search_tree/Solution0108.py)| Easy | Top_100_Liked_Questions, Top_Interview_Questions, Array, Tree, Binary_Tree, Binary_Search_Tree, Divide_and_Conquer | 0 | 100.00
 | 0230 |[Kth Smallest Element in a BST](src/main/python/g0201_0300/s0230_kth_smallest_element_in_a_bst/Solution0230.py)| Medium | Top_100_Liked_Questions, Depth_First_Search, Tree, Binary_Tree, Binary_Search_Tree, Big_O_Time_O(n)_Space_O(n) | 0 | 100.00
+| 0173 |[Binary Search Tree Iterator](src/main/python/g0101_0200/s0173_binary_search_tree_iterator/Solution0173.py)| Medium | Tree, Binary_Tree, Stack, Design, Binary_Search_Tree, Iterator | 2 | 92.39
 
 #### Day 10 Graph/BFS/DFS
 
@@ -377,6 +378,7 @@ Python-based LeetCode algorithm problem solutions, regularly updated.
 | 0136 |[Single Number](src/main/python/g0101_0200/s0136_single_number/Solution0136.py)| Easy | Top_100_Liked_Questions, Top_Interview_Questions, Array, Bit_Manipulation, LeetCode_75_Bit_Manipulation, Big_O_Time_O(N)_Space_O(1) | 0 | 100.00
 | 0007 |[Reverse Integer](src/main/python/g0001_0100/s0007_reverse_integer/Solution0007.py)| Medium | Top_Interview_Questions, Math, Big_O_Time_O(log10(x))_Space_O(1) | 37 | 69.51
 | 0009 |[Palindrome Number](src/main/python/g0001_0100/s0009_palindrome_number/Solution0009.py)| Easy | Math, Big_O_Time_O(log10(x))_Space_O(1) | 4 | 80.28
+| 0172 |[Factorial Trailing Zeroes](src/main/python/g0101_0200/s0172_factorial_trailing_zeroes/Solution0172.py)| Medium | Top_Interview_Questions, Math | 0 | 100.00
 
 #### Udemy Strings
 
@@ -521,6 +523,8 @@ Python-based LeetCode algorithm problem solutions, regularly updated.
 
 | <!-- --> | <!-- --> | <!-- --> | <!-- --> | <!-- --> | <!-- -->
 |-|-|-|-|-|-
+| 0191 |[Number of 1 Bits](src/main/python/g0101_0200/s0191_number_of_1_bits/Solution0191.py)| Easy | Top_Interview_Questions, Bit_Manipulation | 0 | 100.00
+| 0190 |[Reverse Bits](src/main/python/g0101_0200/s0190_reverse_bits/Solution0190.py)| Easy | Top_Interview_Questions, Bit_Manipulation, Divide_and_Conquer | 36 | 75.17
 | 0338 |[Counting Bits](src/main/python/g0301_0400/s0338_counting_bits/Solution0338.py)| Easy | Dynamic_Programming, Bit_Manipulation, LeetCode_75_Bit_Manipulation, Big_O_Time_O(num)_Space_O(num) | 3 | 94.51
 
 #### Udemy Design
@@ -639,6 +643,7 @@ Python-based LeetCode algorithm problem solutions, regularly updated.
 | 0112 |[Path Sum](src/main/python/g0101_0200/s0112_path_sum/Solution0112.py)| Easy | Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree | 0 | 100.00
 | 0129 |[Sum Root to Leaf Numbers](src/main/python/g0101_0200/s0129_sum_root_to_leaf_numbers/Solution0129.py)| Medium | Depth_First_Search, Tree, Binary_Tree | 0 | 100.00
 | 0124 |[Binary Tree Maximum Path Sum](src/main/python/g0101_0200/s0124_binary_tree_maximum_path_sum/Solution0124.py)| Hard | Top_100_Liked_Questions, Top_Interview_Questions, Dynamic_Programming, Depth_First_Search, Tree, Binary_Tree, Big_O_Time_O(N)_Space_O(N) | 11 | 91.40
+| 0173 |[Binary Search Tree Iterator](src/main/python/g0101_0200/s0173_binary_search_tree_iterator/Solution0173.py)| Medium | Tree, Binary_Tree, Stack, Design, Binary_Search_Tree, Iterator | 2 | 92.39
 | 0236 |[Lowest Common Ancestor of a Binary Tree](src/main/python/g0201_0300/s0236_lowest_common_ancestor_of_a_binary_tree/Solution0236.py)| Medium | Top_100_Liked_Questions, Depth_First_Search, Tree, Binary_Tree, LeetCode_75_Binary_Tree/DFS, Big_O_Time_O(n)_Space_O(n) | 41 | 97.74
 
 #### Top Interview 150 Binary Tree BFS
@@ -725,6 +730,8 @@ Python-based LeetCode algorithm problem solutions, regularly updated.
 | <!-- --> | <!-- --> | <!-- --> | <!-- --> | <!-- --> | <!-- -->
 |-|-|-|-|-|-
 | 0067 |[Add Binary](src/main/python/g0001_0100/s0067_add_binary/Solution0067.py)| Easy | String, Math, Bit_Manipulation, Simulation | 0 | 100.00
+| 0190 |[Reverse Bits](src/main/python/g0101_0200/s0190_reverse_bits/Solution0190.py)| Easy | Top_Interview_Questions, Bit_Manipulation, Divide_and_Conquer | 36 | 75.17
+| 0191 |[Number of 1 Bits](src/main/python/g0101_0200/s0191_number_of_1_bits/Solution0191.py)| Easy | Top_Interview_Questions, Bit_Manipulation | 0 | 100.00
 | 0136 |[Single Number](src/main/python/g0101_0200/s0136_single_number/Solution0136.py)| Easy | Top_100_Liked_Questions, Top_Interview_Questions, Array, Bit_Manipulation, LeetCode_75_Bit_Manipulation, Big_O_Time_O(N)_Space_O(1) | 0 | 100.00
 | 0137 |[Single Number II](src/main/python/g0101_0200/s0137_single_number_ii/Solution0137.py)| Medium | Array, Bit_Manipulation | 0 | 100.00
 
@@ -734,6 +741,7 @@ Python-based LeetCode algorithm problem solutions, regularly updated.
 |-|-|-|-|-|-
 | 0009 |[Palindrome Number](src/main/python/g0001_0100/s0009_palindrome_number/Solution0009.py)| Easy | Math, Big_O_Time_O(log10(x))_Space_O(1) | 4 | 80.28
 | 0066 |[Plus One](src/main/python/g0001_0100/s0066_plus_one/Solution0066.py)| Easy | Top_Interview_Questions, Array, Math | 0 | 100.00
+| 0172 |[Factorial Trailing Zeroes](src/main/python/g0101_0200/s0172_factorial_trailing_zeroes/Solution0172.py)| Medium | Top_Interview_Questions, Math | 0 | 100.00
 
 #### Top Interview 150 1D DP
 
@@ -756,6 +764,7 @@ Python-based LeetCode algorithm problem solutions, regularly updated.
 | 0097 |[Interleaving String](src/main/python/g0001_0100/s0097_interleaving_string/Solution0097.py)| Medium | String, Dynamic_Programming | 37 | 90.93
 | 0072 |[Edit Distance](src/main/python/g0001_0100/s0072_edit_distance/Solution0072.py)| Medium | Top_100_Liked_Questions, String, Dynamic_Programming, LeetCode_75_DP/Multidimensional, Big_O_Time_O(n^2)_Space_O(n2) | 23 | 98.84
 | 0123 |[Best Time to Buy and Sell Stock III](src/main/python/g0101_0200/s0123_best_time_to_buy_and_sell_stock_iii/Solution0123.py)| Hard | Array, Dynamic_Programming | 232 | 75.22
+| 0188 |[Best Time to Buy and Sell Stock IV](src/main/python/g0101_0200/s0188_best_time_to_buy_and_sell_stock_iv/Solution.java)| Hard | Array, Dynamic_Programming | 1 | 99.73
 | 0221 |[Maximal Square](src/main/python/g0201_0300/s0221_maximal_square/Solution0221.py)| Medium | Array, Dynamic_Programming, Matrix, Big_O_Time_O(m\*n)_Space_O(m\*n) | 129 | 64.49
 
 ### Data Structure I
@@ -956,6 +965,7 @@ Python-based LeetCode algorithm problem solutions, regularly updated.
 | <!-- --> | <!-- --> | <!-- --> | <!-- --> | <!-- --> | <!-- -->
 |-|-|-|-|-|-
 | 0230 |[Kth Smallest Element in a BST](src/main/python/g0201_0300/s0230_kth_smallest_element_in_a_bst/Solution0230.py)| Medium | Top_100_Liked_Questions, Depth_First_Search, Tree, Binary_Tree, Binary_Search_Tree, Big_O_Time_O(n)_Space_O(n) | 0 | 100.00
+| 0173 |[Binary Search Tree Iterator](src/main/python/g0101_0200/s0173_binary_search_tree_iterator/Solution0173.py)| Medium | Tree, Binary_Tree, Stack, Design, Binary_Search_Tree, Iterator | 2 | 92.39
 
 #### Day 18 Tree
 
@@ -1059,11 +1069,13 @@ Python-based LeetCode algorithm problem solutions, regularly updated.
 
 | <!-- --> | <!-- --> | <!-- --> | <!-- --> | <!-- --> | <!-- -->
 |-|-|-|-|-|-
+| 0191 |[Number of 1 Bits](src/main/python/g0101_0200/s0191_number_of_1_bits/Solution0191.py)| Easy | Top_Interview_Questions, Bit_Manipulation | 0 | 100.00
 
 #### Day 14 Bit Manipulation
 
 | <!-- --> | <!-- --> | <!-- --> | <!-- --> | <!-- --> | <!-- -->
 |-|-|-|-|-|-
+| 0190 |[Reverse Bits](src/main/python/g0101_0200/s0190_reverse_bits/Solution0190.py)| Easy | Top_Interview_Questions, Bit_Manipulation, Divide_and_Conquer | 36 | 75.17
 | 0136 |[Single Number](src/main/python/g0101_0200/s0136_single_number/Solution0136.py)| Easy | Top_100_Liked_Questions, Top_Interview_Questions, Array, Bit_Manipulation, LeetCode_75_Bit_Manipulation, Big_O_Time_O(N)_Space_O(1) | 0 | 100.00
 
 ### Algorithm II
@@ -1512,6 +1524,7 @@ Python-based LeetCode algorithm problem solutions, regularly updated.
 
 | <!-- --> | <!-- --> | <!-- --> | <!-- --> | <!-- --> | <!-- -->
 |-|-|-|-|-|-
+| 0191 |[Number of 1 Bits](src/main/python/g0101_0200/s0191_number_of_1_bits/Solution0191.py)| Easy | Top_Interview_Questions, Bit_Manipulation | 0 | 100.00
 
 #### Day 3 Conditional Statements
 
@@ -1659,6 +1672,7 @@ Python-based LeetCode algorithm problem solutions, regularly updated.
 | <!-- --> | <!-- --> | <!-- --> | <!-- --> | <!-- --> | <!-- -->
 |-|-|-|-|-|-
 | 0061 |[Rotate List](src/main/python/g0001_0100/s0061_rotate_list/Solution0061.py)| Medium | Two_Pointers, Linked_List | 0 | 100.00
+| 0173 |[Binary Search Tree Iterator](src/main/python/g0101_0200/s0173_binary_search_tree_iterator/Solution0173.py)| Medium | Tree, Binary_Tree, Stack, Design, Binary_Search_Tree, Iterator | 2 | 92.39
 
 #### Day 17
 
@@ -1717,7 +1731,12 @@ Python-based LeetCode algorithm problem solutions, regularly updated.
 | 0206 |[Reverse Linked List](src/main/python/g0201_0300/s0206_reverse_linked_list/Solution0206.py)| Easy | Top_100_Liked_Questions, Top_Interview_Questions, Linked_List, Recursion, LeetCode_75_LinkedList, Data_Structure_I_Day_8_Linked_List, Algorithm_I_Day_10_Recursion_Backtracking, Level_1_Day_3_Linked_List, Udemy_Linked_List, Big_O_Time_O(N)_Space_O(1) | 0 | 100.00
 | 0200 |[Number of Islands](src/main/python/g0101_0200/s0200_number_of_islands/Solution0200.py)| Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Depth_First_Search, Breadth_First_Search, Matrix, Union_Find, Algorithm_II_Day_6_Breadth_First_Search_Depth_First_Search, Graph_Theory_I_Day_1_Matrix_Related_Problems, Level_1_Day_9_Graph/BFS/DFS, Udemy_Graph, Top_Interview_150_Graph_General, Big_O_Time_O(M\*N)_Space_O(M\*N) | 234 | 82.73
 | 0198 |[House Robber](src/main/python/g0101_0200/s0198_house_robber/Solution0198.py)| Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, LeetCode_75_DP/1D, Algorithm_I_Day_12_Dynamic_Programming, Dynamic_Programming_I_Day_3, Level_2_Day_12_Dynamic_Programming, Udemy_Dynamic_Programming, Top_Interview_150_1D_DP, Big_O_Time_O(n)_Space_O(n) | 0 | 100.00
+| 0191 |[Number of 1 Bits](src/main/python/g0101_0200/s0191_number_of_1_bits/Solution0191.py)| Easy | Top_Interview_Questions, Bit_Manipulation, Algorithm_I_Day_13_Bit_Manipulation, Programming_Skills_I_Day_2_Operator, Udemy_Bit_Manipulation, Top_Interview_150_Bit_Manipulation | 0 | 100.00
+| 0190 |[Reverse Bits](src/main/python/g0101_0200/s0190_reverse_bits/Solution0190.py)| Easy | Top_Interview_Questions, Bit_Manipulation, Divide_and_Conquer, Algorithm_I_Day_14_Bit_Manipulation, Udemy_Bit_Manipulation, Top_Interview_150_Bit_Manipulation | 36 | 75.17
 | 0189 |[Rotate Array](src/main/python/g0101_0200/s0189_rotate_array/Solution0189.py)| Medium | Top_100_Liked_Questions, Top_Interview_Questions, Array, Math, Two_Pointers, Algorithm_I_Day_2_Two_Pointers, Udemy_Arrays, Top_Interview_150_Array/String, Big_O_Time_O(n)_Space_O(1) | 3 | 74.65
+| 0188 |[Best Time to Buy and Sell Stock IV](src/main/python/g0101_0200/s0188_best_time_to_buy_and_sell_stock_iv/Solution.java)| Hard | Array, Dynamic_Programming, Top_Interview_150_Multidimensional_DP | 1 | 99.73
+| 0173 |[Binary Search Tree Iterator](src/main/python/g0101_0200/s0173_binary_search_tree_iterator/Solution0173.py)| Medium | Tree, Binary_Tree, Stack, Design, Binary_Search_Tree, Iterator, Data_Structure_II_Day_17_Tree, Programming_Skills_II_Day_16, Level_2_Day_9_Binary_Search_Tree, Top_Interview_150_Binary_Tree_General | 2 | 92.39
+| 0172 |[Factorial Trailing Zeroes](src/main/python/g0101_0200/s0172_factorial_trailing_zeroes/Solution0172.py)| Medium | Top_Interview_Questions, Math, Udemy_Integers, Top_Interview_150_Math | 0 | 100.00
 | 0169 |[Majority Element](src/main/python/g0101_0200/s0169_majority_element/Solution0169.py)| Easy | Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Sorting, Counting, Divide_and_Conquer, Data_Structure_II_Day_1_Array, Udemy_Famous_Algorithm, Top_Interview_150_Array/String, Big_O_Time_O(n)_Space_O(1) | 7 | 56.72
 | 0167 |[Two Sum II - Input Array Is Sorted](src/main/python/g0101_0200/s0167_two_sum_ii_input_array_is_sorted/Solution0167.py)| Medium | Array, Binary_Search, Two_Pointers, Algorithm_I_Day_3_Two_Pointers, Binary_Search_I_Day_7, Top_Interview_150_Two_Pointers | 3 | 80.89
 | 0162 |[Find Peak Element](src/main/python/g0101_0200/s0162_find_peak_element/Solution0162.py)| Medium | Top_Interview_Questions, Array, Binary_Search, LeetCode_75_Binary_Search, Algorithm_II_Day_2_Binary_Search, Binary_Search_II_Day_12, Top_Interview_150_Binary_Search | 0 | 100.00

src/main/python/g0101_0200/s0172_factorial_trailing_zeroes/Solution0172.py

@@ -0,0 +1,11 @@
+# #Medium #Top_Interview_Questions #Math #Udemy_Integers #Top_Interview_150_Math
+# #2025_09_14_Time_0_ms_(100.00%)_Space_17.76_MB_(53.50%)
+
+class Solution:
+    def trailingZeroes(self, n: int) -> int:
+        base = 5
+        count = 0
+        while n >= base:
+            count += n // base
+            base = base * 5
+        return count

src/main/python/g0101_0200/s0172_factorial_trailing_zeroes/Solution0172_test.py

@@ -0,0 +1,12 @@
+import unittest
+from Solution0172 import Solution
+
+class SolutionTest(unittest.TestCase):
+    def test_trailingZeroes(self):
+        self.assertEqual(Solution().trailingZeroes(3), 0)
+
+    def test_trailingZeroes2(self):
+        self.assertEqual(Solution().trailingZeroes(5), 1)
+
+    def test_trailingZeroes3(self):
+        self.assertEqual(Solution().trailingZeroes(0), 0)

src/main/python/g0101_0200/s0172_factorial_trailing_zeroes/readme.md

@@ -0,0 +1,35 @@
+172\. Factorial Trailing Zeroes
+
+Medium
+
+Given an integer `n`, return _the number of trailing zeroes in_ `n!`.
+
+Note that `n! = n * (n - 1) * (n - 2) * ... * 3 * 2 * 1`.
+
+**Example 1:**
+
+**Input:** n = 3
+
+**Output:** 0
+
+**Explanation:** 3! = 6, no trailing zero. 
+
+**Example 2:**
+
+**Input:** n = 5
+
+**Output:** 1
+
+**Explanation:** 5! = 120, one trailing zero. 
+
+**Example 3:**
+
+**Input:** n = 0
+
+**Output:** 0 
+
+**Constraints:**
+
+*   <code>0 <= n <= 10<sup>4</sup></code>
+
+**Follow up:** Could you write a solution that works in logarithmic time complexity?

src/main/python/g0101_0200/s0173_binary_search_tree_iterator/Solution0173.py

@@ -0,0 +1,47 @@
+# #Medium #Tree #Binary_Tree #Stack #Design #Binary_Search_Tree #Iterator
+# #Data_Structure_II_Day_17_Tree #Programming_Skills_II_Day_16 #Level_2_Day_9_Binary_Search_Tree
+# #Top_Interview_150_Binary_Tree_General #2025_09_14_Time_2_ms_(92.39%)_Space_25.20_MB_(18.38%)
+
+from typing import Optional
+
+class TreeNode:
+    def __init__(self, val=0, left=None, right=None):
+        self.val = val
+        self.left = left
+        self.right = right
+
+# Definition for a binary tree node.
+# class TreeNode:
+#     def __init__(self, val=0, left=None, right=None):
+#         self.val = val
+#         self.left = left
+#         self.right = right
+class BSTIterator:
+    def __init__(self, root: Optional[TreeNode]):
+        self.stack = []
+        self._push_left(root)
+    
+    def _push_left(self, node):
+        # Push all left children
+        while node:
+            self.stack.append(node)
+            node = node.left
+    
+    def next(self) -> int:
+        # Smallest available node
+        node = self.stack.pop()
+        # If node has a right child → push its left subtree
+        if node.right:
+            self._push_left(node.right)
+        return node.val
+    
+    def hasNext(self) -> bool:
+        return len(self.stack) > 0
+
+        
+
+
+# Your BSTIterator object will be instantiated and called as such:
+# obj = BSTIterator(root)
+# param_1 = obj.next()
+# param_2 = obj.hasNext()

src/main/python/g0101_0200/s0173_binary_search_tree_iterator/Solution0173_test.py

@@ -0,0 +1,20 @@
+import unittest
+from Solution0173 import BSTIterator, TreeNode
+
+class BSTIteratorTest(unittest.TestCase):
+    def test_iteratorBST(self):
+        left = TreeNode(3)
+        right = TreeNode(15)
+        right.left = TreeNode(9)
+        right.right = TreeNode(20)
+        root = TreeNode(7, left, right)
+        iterator = BSTIterator(root)
+        self.assertEqual(iterator.next(), 3)
+        self.assertEqual(iterator.next(), 7)
+        self.assertTrue(iterator.hasNext())
+        self.assertEqual(iterator.next(), 9)
+        self.assertTrue(iterator.hasNext())
+        self.assertEqual(iterator.next(), 15)
+        self.assertTrue(iterator.hasNext())
+        self.assertEqual(iterator.next(), 20)
+        self.assertFalse(iterator.hasNext())

src/main/python/g0101_0200/s0173_binary_search_tree_iterator/readme.md

@@ -0,0 +1,44 @@
+173\. Binary Search Tree Iterator
+
+Medium
+
+Implement the `BSTIterator` class that represents an iterator over the **[in-order traversal](https://en.wikipedia.org/wiki/Tree_traversal#In-order_(LNR))** of a binary search tree (BST):
+
+*   `BSTIterator(TreeNode root)` Initializes an object of the `BSTIterator` class. The `root` of the BST is given as part of the constructor. The pointer should be initialized to a non-existent number smaller than any element in the BST.
+*   `boolean hasNext()` Returns `true` if there exists a number in the traversal to the right of the pointer, otherwise returns `false`.
+*   `int next()` Moves the pointer to the right, then returns the number at the pointer.
+
+Notice that by initializing the pointer to a non-existent smallest number, the first call to `next()` will return the smallest element in the BST.
+
+You may assume that `next()` calls will always be valid. That is, there will be at least a next number in the in-order traversal when `next()` is called.
+
+**Example 1:**
+
+![](https://assets.leetcode.com/uploads/2018/12/25/bst-tree.png)
+
+**Input** ["BSTIterator", "next", "next", "hasNext", "next", "hasNext", "next", "hasNext", "next", "hasNext"] [[[7, 3, 15, null, null, 9, 20]], [], [], [], [], [], [], [], [], []]
+
+**Output:** [null, 3, 7, true, 9, true, 15, true, 20, false]
+
+**Explanation:**
+
+    BSTIterator bSTIterator = new BSTIterator([7, 3, 15, null, null, 9, 20]);
+    bSTIterator.next(); // return 3
+    bSTIterator.next(); // return 7
+    bSTIterator.hasNext(); // return True
+    bSTIterator.next(); // return 9
+    bSTIterator.hasNext(); // return True
+    bSTIterator.next(); // return 15
+    bSTIterator.hasNext(); // return True
+    bSTIterator.next(); // return 20
+    bSTIterator.hasNext(); // return False 
+
+**Constraints:**
+
+*   The number of nodes in the tree is in the range <code>[1, 10<sup>5</sup>]</code>.
+*   <code>0 <= Node.val <= 10<sup>6</sup></code>
+*   At most <code>10<sup>5</sup></code> calls will be made to `hasNext`, and `next`.
+
+**Follow up:**
+
+*   Could you implement `next()` and `hasNext()` to run in average `O(1)` time and use `O(h)` memory, where `h` is the height of the tree?

src/main/python/g0101_0200/s0188_best_time_to_buy_and_sell_stock_iv/Solution.java

@@ -0,0 +1,23 @@
+package g0101_0200.s0188_best_time_to_buy_and_sell_stock_iv;
+
+// #Hard #Array #Dynamic_Programming #Top_Interview_150_Multidimensional_DP
+// #2025_03_09_Time_1_ms_(99.73%)_Space_41.76_MB_(82.48%)
+
+public class Solution {
+    public int maxProfit(int k, int[] prices) {
+        int n = prices.length;
+        int[] dp = new int[k + 1];
+        int[] maxdp = new int[k + 1];
+        for (int i = 0; i <= k; i++) {
+            maxdp[i] = Integer.MIN_VALUE;
+        }
+        for (int i = 1; i <= n; i++) {
+            maxdp[0] = Math.max(maxdp[0], dp[0] - prices[i - 1]);
+            for (int j = k; j >= 1; j--) {
+                maxdp[j] = Math.max(maxdp[j], dp[j] - prices[i - 1]);
+                dp[j] = Math.max(maxdp[j - 1] + prices[i - 1], dp[j]);
+            }
+        }
+        return dp[k];
+    }
+}

src/main/python/g0101_0200/s0188_best_time_to_buy_and_sell_stock_iv/Solution0188.py

@@ -0,0 +1,18 @@
+# #Hard #Array #Dynamic_Programming #Top_Interview_150_Multidimensional_DP
+# #2025_09_14_Time_50_ms_(80.74%)_Space_17.88_MB_(83.54%)
+
+from typing import List
+
+class Solution:
+    def maxProfit(self, k: int, prices: List[int]) -> int:
+        n = len(prices)
+        dp = [0] * (k + 1)
+        maxdp = [float('-inf')] * (k + 1)
+        
+        for i in range(1, n + 1):
+            maxdp[0] = max(maxdp[0], dp[0] - prices[i - 1])
+            for j in range(k, 0, -1):
+                maxdp[j] = max(maxdp[j], dp[j] - prices[i - 1])
+                dp[j] = max(maxdp[j - 1] + prices[i - 1], dp[j])
+        
+        return dp[k]