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## Discussion of Problem 2111. Plato

solution
Posted by Wonsei 19 Sep 2020 04:20
sort the array. maintain W, the total weight of the array.
start from the smallest element and add A[i] * W to ANS.
subtract A[i] from W.
Re: solution
Posted by Egor 20 Sep 2020 21:49
There is a better solution with O(1) memory and O(n) time (without sorting).

Edited by author 20.09.2020 21:51

Edited by author 20.09.2020 21:51
Re: solution
Posted by Littel_John 5 Nov 2020 16:38
Do you mind sharing this solution?
I solved it using sorting but cannot think of another solution.
Re: solution
Posted by Conformist 3 Dec 2020 15:53
answer = (sum of array) ^ 2
You can get it by simple math.
Littel_John wrote 5 November 2020 16:38
Do you mind sharing this solution?
I solved it using sorting but cannot think of another solution.