math clear solution for Missing Number by kdim - python coding challenges

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math solution in Clear category for Missing Number by kdim

def missing_number(items: list[int]) -> int:
    return (min(items) + max(items)) * (len(items) + 1) / 2 - sum(items)


print("Example:")
print(missing_number([1, 4, 2, 5]))

assert missing_number([1, 4, 2, 5]) == 3
assert missing_number([2, 6, 8]) == 4

print("The mission is done! Click 'Check Solution' to earn rewards!")

Sept. 24, 2022

Comments:

U.V on Jan. 25, 2023, 2:07 p.m.
Simple and clear

hbczmxy on Jan. 30, 2023, 6:15 a.m.
Your solution is really great! I love it so much!

H0r4c3 on Feb. 4, 2023, 7:57 a.m.
Very good idea with min and max! And everything in one line!

sarahsorlien on Feb. 7, 2023, 2:19 p.m.
Doesn't it return a float not an int?

adamspj on Jan. 31, 2024, 7:28 p.m.
It looks like it should, but I'm not sure whether the type declaration on the function ("-> int") causes it to cast the return as an int automatically?

adamspj on Jan. 31, 2024, 9:07 p.m.
No, actually, it is returning a float. The assertion 3.0 == 3 will pass. The problem should be modified to explicitly accept a number return, or to make the asserts only accept int.

BootzenKatzen on June 22, 2023, 1:05 p.m.
I really don't know how you figured out that math, but the resulting function is pretty simple and easy to understand, even if I don't understand how you got there. Great work! I guess I need to brush up on some math!

adamspj on Jan. 31, 2024, 7:25 p.m.
I think this illustrates why the solution given may be clever, but it's not clear. A clear solution should be easy to read, parse, and understand.

tamagoyaki on Nov. 2, 2023, 4:59 a.m.
Genius solution! I like this!

jrchionis on Aug. 21, 2024, 6:01 p.m.
Why didn't I think of that :sweat

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