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why should we sort 2024-day1 ?
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this post was submitted on 21 Mar 2025
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True, that is what I did when substracting the sorted lists. I calculated their absolutes.
But I still don't understand why the unsorted method doesn't work. Can you give an example of two lists which this method doesn't work with? Because whatever example I calculated, it was correct.
There's a way to make two length-two lists from 1, 2, 3, 4 that will give you a counter-example.
gives 27
But
gives 11
You are right. Although the way I was talking about is |(2+10)-(1+20)|= 9 Seems like I coincidentally created some example lists that all worked with this method!
And the algebraic reason would be the presence of parenthesis. |(a+b)-(c+d)| != |(a-c)|+|(b-d)|