From 0bdbc5deb72878ca633bb3b99e07515e2cbd809c Mon Sep 17 00:00:00 2001 From: mervereis Date: Tue, 13 Oct 2026 21:54:14 +0100 Subject: [PATCH 1/3] Implement caching in Fibonacci function to improve performance --- Sprint-2/improve_with_caches/fibonacci/fibonacci.py | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/Sprint-2/improve_with_caches/fibonacci/fibonacci.py b/Sprint-2/improve_with_caches/fibonacci/fibonacci.py index 60cc6671..55ad3c16 100644 --- a/Sprint-2/improve_with_caches/fibonacci/fibonacci.py +++ b/Sprint-2/improve_with_caches/fibonacci/fibonacci.py @@ -1,4 +1,15 @@ +cache = {} + def fibonacci(n): + if n < 0: + raise ValueError("n must be non-negative") + if n <= 1: return n - return fibonacci(n - 1) + fibonacci(n - 2) + + if n in cache: + return cache[n] + + cache[n] = fibonacci(n - 1) + fibonacci(n - 2) + + return cache[n] \ No newline at end of file From 717948ec80869f6d7883bddd54342c4a5b8f3f1b Mon Sep 17 00:00:00 2001 From: mervereis Date: Tue, 13 Oct 2026 21:57:45 +0100 Subject: [PATCH 2/3] Implement caching in ways_to_make_change to optimize performance --- .../making_change/making_change.py | 43 ++++++++++--------- 1 file changed, 22 insertions(+), 21 deletions(-) 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 255612e5..048ecfea 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 +1,33 @@ from typing import List +cache = {} 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]) + coins = [200, 100, 50, 20, 10, 5, 2, 1] + return ways_to_make_change_helper(total, coins) 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: + if total == 0: + return 1 + + if total < 0 or len(coins) == 0: return 0 + key = (total, tuple(coins)) + + if key in cache: + return cache[key] + + coin = coins[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 + + for count in range(total // coin + 1): + remaining = total - count * coin + + ways += ways_to_make_change_helper(remaining, coins[1:]) + + cache[key] = ways + return ways From f8eea94e9c0a201f77a18390b1f97391d3940343 Mon Sep 17 00:00:00 2001 From: mervereis Date: Thu, 15 Oct 2026 21:05:38 +0100 Subject: [PATCH 3/3] Refactor ways_to_make_change to use a fixed COINS tuple and simplify parameters --- .../making_change/making_change.py | 16 +++++++--------- 1 file changed, 7 insertions(+), 9 deletions(-) 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 048ecfea..5f87071b 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 +1,30 @@ -from typing import List - +COINS = (200, 100, 50, 20, 10, 5, 2, 1) cache = {} def ways_to_make_change(total: int) -> int: - coins = [200, 100, 50, 20, 10, 5, 2, 1] - return ways_to_make_change_helper(total, coins) + return ways_to_make_change_helper(total, 0) -def ways_to_make_change_helper(total: int, coins: List[int]) -> int: +def ways_to_make_change_helper(total: int, coin_index: int) -> int: if total == 0: return 1 - if total < 0 or len(coins) == 0: + if total < 0 or coin_index == len(COINS): return 0 - key = (total, tuple(coins)) + key = (total, coin_index) if key in cache: return cache[key] - coin = coins[0] + coin = COINS[coin_index] ways = 0 for count in range(total // coin + 1): remaining = total - count * coin - ways += ways_to_make_change_helper(remaining, coins[1:]) + ways += ways_to_make_change_helper(remaining, coin_index + 1) cache[key] = ways