Problem 1154. Identify the heavier bag

Created by HARISANKAR PS

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Last Solution submitted on Jun 06, 2023

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@bmtran (Bryant Tran) on 31 Dec 2012

I think it only takes 5 weighings when N=128. Am I incorrect?

Alfonso Nieto-Castanon on 31 Dec 2012

agree 5 weighing for N=128 (worst case scenario you reduce to 43 15 5 2 1 after each consecutive weighing)

trekker on 2 Jan 2013

the last test case provided by the author is wrong: should be 5 since log(128)/log(3) < 5.

Rafael S.T. Vieira on 2 Sep 2020

The problem is that the author do not specify an strategy. And as mentioned, dividing by 3 yields a better strategy than 6 weightings for 128. But, my guess is that the author counted the number of divisions instead of the number of weightings 128->[42 42 43] -> [14 14 14; 14 14 15]->[5 5 4; 5 5 5]->[2 2 0; 2 2 1]->[1;2]->1.

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Problem 1154. Identify the heavier bag

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Problem 1154. Identify the heavier bag

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