West Midlands | 25-SDC-July | Gabriel Deng | Sprint 2 | Improve with caches#71
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gai93003 wants to merge 1 commit intoCodeYourFuture:mainfrom
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West Midlands | 25-SDC-July | Gabriel Deng | Sprint 2 | Improve with caches#71gai93003 wants to merge 1 commit intoCodeYourFuture:mainfrom
gai93003 wants to merge 1 commit intoCodeYourFuture:mainfrom
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gai93003
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📅 Sprint 2
cjyuan
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Jan 23, 2026
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| @@ -29,4 +36,6 @@ def ways_to_make_change_helper(total: int, coins: List[int]) -> int: | |||
| intermediate = ways_to_make_change_helper(total - total_from_coins, coins=coins[coin_index+1:]) | |||
| ways += intermediate | |||
| count_of_coin += 1 | |||
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From line 36, we can figure out coins can only be one of the following 9 lists:
[200, 100, 50, 20, 10, 5, 2, 1]
[100, 50, 20, 10, 5, 2, 1]
[50, 20, 10, 5, 2, 1]
...
[1]
[]
We could further improve the performance if we can
- avoid repeatedly creating the same sub-lists at line 36, and
- create key as
(total, a_value_identifiying_one_of_the_sublists)instead of as(total, tuple(coins))
I don't think this exercise expects trainees to optimize the code to this level. So change is optional.
cjyuan
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