The following situation doesn't checked in tests or the problem statement is incorrect.
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2
Cocoa-butter 1 1000
Cocoa-powder 1 9000
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Here we have weights written in increasing order (problem says: they should be in non-increasing order!).

My solution checks this and gets WA. But the solution from forum says YES and gets AC. ;)

You are right. N = 5000 in test 3. The problem statement is fixed.