diff --git a/Sprint-2/improve_with_caches/fibonacci/fibonacci.py b/Sprint-2/improve_with_caches/fibonacci/fibonacci.py index 60cc667..ccceec1 100644 --- a/Sprint-2/improve_with_caches/fibonacci/fibonacci.py +++ b/Sprint-2/improve_with_caches/fibonacci/fibonacci.py @@ -1,4 +1,13 @@ +cache = {} + def fibonacci(n): + if n in cache: + return cache[n] + if n <= 1: - return n - return fibonacci(n - 1) + fibonacci(n - 2) + result = n + else: + result = fibonacci(n - 1) + fibonacci(n - 2) + + cache[n] = result + return result diff --git a/Sprint-2/improve_with_caches/making_change/making_change.py b/Sprint-2/improve_with_caches/making_change/making_change.py index 255612e..0acf3b4 100644 --- a/Sprint-2/improve_with_caches/making_change/making_change.py +++ b/Sprint-2/improve_with_caches/making_change/making_change.py @@ -1,32 +1,38 @@ -from typing import List - - 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. """ - return ways_to_make_change_helper(total, [200, 100, 50, 20, 10, 5, 2, 1]) + cache = {} + coins = (200, 100, 50, 20, 10, 5, 2, 1) + return ways_to_make_change_helper(total, coins, 0, cache) -def ways_to_make_change_helper(total: int, coins: List[int]) -> int: +def ways_to_make_change_helper(total: int, coins: tuple, coin_index: int, cache: dict) -> int: """ Helper function for ways_to_make_change to avoid exposing the coins parameter to callers. """ - if total == 0 or len(coins) == 0: + if total == 0 or coin_index >= len(coins): return 0 + cache_key = (total, coin_index) + + if cache_key in cache: + return cache[cache_key] + ways = 0 - for coin_index in range(len(coins)): - coin = coins[coin_index] + for i in range(coin_index, len(coins)): + coin = coins[i] 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:]) + intermediate = ways_to_make_change_helper(total - total_from_coins, coins, i + 1, cache) ways += intermediate count_of_coin += 1 + + cache[cache_key] = ways return ways