diverta2019_2_C
https://gyazo.com/b445456237ffb73c3e17a53ff8a93a4b
Thoughts.
When the number is two, subtract the smaller one from the larger one.
What about when there are three?
c-(a-b) is in essence c-a+b
That is, N/2 units are negative.
Then we can sort and set the smaller half to negative.
Official Explanation
You're missing (a-b)-c when you have three.
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