adding algo

src/my_project/interviews/top_150_questions_round_22/ex_144_best_time_to_buy_stock_iv.py

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+from typing import List
+
+
+class Solution:
+    def maxProfit(self, k: int, prices: List[int]) -> int:
+        n = len(prices)
+        if n == 0 or k == 0:
+            return 0
+
+        if k >= n // 2:
+            return sum(
+                max(prices[i + 1] - prices[i], 0) for i in range(n - 1)
+            )
+
+        buy = [float('-inf')] * (k + 1)
+        sell = [0] * (k + 1)
+
+        for price in prices:
+            for j in range(1, k + 1):
+                buy[j] = max(buy[j], sell[j - 1] - price)
+                sell[j] = max(sell[j], buy[j] + price)
+
+        return sell[k]

src/my_project/interviews_typescript/top_150_questions_round_1/ex_144_best_time_to_buy_stock_iv.ts

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+function maxProfitIV(k: number, prices: number[]): number {
+    const n = prices.length;
+    if (n === 0 || k === 0) return 0;
+
+    if (k >= Math.floor(n / 2)) {
+        let profit = 0;
+        for (let i = 1; i < n; i++) {
+            if (prices[i] > prices[i - 1]) profit += prices[i] - prices[i - 1];
+        }
+        return profit;
+    }
+
+    const buy: number[] = new Array(k + 1).fill(-Infinity);
+    const sell: number[] = new Array(k + 1).fill(0);
+
+    for (const price of prices) {
+        for (let j = 1; j <= k; j++) {
+            buy[j] = Math.max(buy[j], sell[j - 1] - price);
+            sell[j] = Math.max(sell[j], buy[j] + price);
+        }
+    }
+
+    return sell[k];
+};

tests/test_150_questions_round_22/test_144_best_time_to_buy_stock_iv_round_22.py

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+import unittest
+from src.my_project.interviews.top_150_questions_round_22\
+.ex_144_best_time_to_buy_stock_iv import Solution
+
+
+class BestTimeToBuyStockIVTestCase(unittest.TestCase):
+    def setUp(self):
+        self.solution = Solution()
+
+    def test_example_1(self):
+        self.assertEqual(2, self.solution.maxProfit(2, [2, 4, 1]))
+
+    def test_example_2(self):
+        self.assertEqual(7, self.solution.maxProfit(2, [3, 2, 6, 5, 0, 3]))
+
+    def test_single_price(self):
+        self.assertEqual(0, self.solution.maxProfit(1, [5]))
+
+    def test_no_profit(self):
+        self.assertEqual(0, self.solution.maxProfit(2, [5, 4, 3, 2, 1]))
+
+    def test_k_exceeds_half_n(self):
+        self.assertEqual(7, self.solution.maxProfit(10, [1, 3, 2, 5, 4, 6]))
+
+
+if __name__ == '__main__':
+    unittest.main()