DraftRoman · DraftRoman · Jun 11, 2026 · Jun 11, 2026 · Jun 11, 2026
diff --git a/Sprint-2/improve_with_caches/fibonacci/fibonacci.py b/Sprint-2/improve_with_caches/fibonacci/fibonacci.py
@@ -1,4 +1,12 @@
-def fibonacci(n):
-    if n <= 1:
-        return n
-    return fibonacci(n - 1) + fibonacci(n - 2)
+class Fibonacci:
+    def __init__(self):
+        self.cache = {0: 0, 1: 1}
+
+    def __call__(self, n):
+        if n in self.cache:
+            return self.cache[n]
+
+        self.cache[n] = self(n - 1) + self(n - 2)
+        return self.cache[n]
+
+fibonacci = Fibonacci()
diff --git a/Sprint-2/improve_with_caches/fibonacci/fibonacci_test.py b/Sprint-2/improve_with_caches/fibonacci/fibonacci_test.py
@@ -18,6 +18,8 @@ def test_3(self):
     def test_10(self):
         self.assertEqual(fibonacci(10), 55)
 
+    def test_50(self):
+        self.assertEqual(fibonacci(50), 12586269025)
     def test_200(self):
         self.assertEqual(fibonacci(200), 280571172992510140037611932413038677189525)
 

diff --git a/Sprint-2/improve_with_caches/making_change/coin.py b/Sprint-2/improve_with_caches/making_change/coin.py
@@ -0,0 +1,5 @@
+class Coin:
+    def __init__(self, name: str, value: int):
+        self.name = name
+        self.value = value
+
diff --git a/Sprint-2/improve_with_caches/making_change/making_change.py b/Sprint-2/improve_with_caches/making_change/making_change.py
@@ -1,32 +1,41 @@
-from typing import List
+from functools import lru_cache
+from coin import Coin
+
+COINS = [
+    Coin("200 coins", 200),
+    Coin("100 coins", 100),
+    Coin("50 coins", 50),
+    Coin("20 coins", 20),
+    Coin("10 coins", 10),
+    Coin("5 coins", 5),
+    Coin("2 coins", 2),
+    Coin("1 coin", 1),
+]
 
 
 def ways_to_make_change(total: int) -> int:
     """
-    Given access to coins with the values 1, 2, 5, 10, 20, 50, 100, 200, returns a count of all of the ways to make the passed total value.
-
-    For instance, there are two ways to make a value of 3: with 3x 1 coins, or with 1x 1 coin and 1x 2 coin.
+    Given access to coins with the values 1, 2, 5, 10, 20, 50, 100, 200,
+    returns the number of ways to make the total.
     """
-    return ways_to_make_change_helper(total, [200, 100, 50, 20, 10, 5, 2, 1])
+    @lru_cache(maxsize=None)
+    def helper(remaining: int, index: int) -> int:
+
+        if remaining == 0:
+            return 1
+
+        if index == len(COINS):
+            return 0
 
+        ways = 0
+        coin = COINS[index]
 
-def ways_to_make_change_helper(total: int, coins: List[int]) -> int:
-    """
-    Helper function for ways_to_make_change to avoid exposing the coins parameter to callers.
-    """
-    if total == 0 or len(coins) == 0:
-        return 0
-
-    ways = 0
-    for coin_index in range(len(coins)):
-        coin = coins[coin_index]
-        count_of_coin = 1
-        while coin * count_of_coin <= total:
-            total_from_coins = coin * count_of_coin
-            if total_from_coins == total:
-                ways += 1
-            else:
-                intermediate = ways_to_make_change_helper(total - total_from_coins, coins=coins[coin_index+1:])
-                ways += intermediate
-            count_of_coin += 1
-    return ways
+        max_count = remaining 
+
+        for count in range(max_count + 1):
+            new_remaining = remaining - count * coin.value
+            ways += helper(new_remaining, index + 1)
+
+        return ways
+
+    return helper(total, 0)
diff --git a/Sprint-2/improve_with_caches/making_change/making_change_test.py b/Sprint-2/improve_with_caches/making_change/making_change_test.py
@@ -24,6 +24,8 @@ def test_7(self):
     def test_17(self):
         self.assertEqual(ways_to_make_change(17), 28)
 
+    def test_100(self):
+        self.assertEqual(ways_to_make_change(100), 4563)
     def test_9176(self):
         self.assertEqual(ways_to_make_change(9176), 628431158425225)