What is the proof behind Half Sequence's Solution (Codechef Cook-Off) ?

Revision en2, by aopo, 2021-09-20 11:21:06

The official editorial of the Half Sequence says

Reason they give

But, what is the proof behind it? I mean what is the intution behind saying this? Can someone give a formal proof for it.


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en1 English aopo 2021-09-20 11:18:19 789 Initial revision (published)