2011 OIM Problems/Problem 6
Problem
Let and be positive integers, with . In a straight line there are stones of different colors such that we have stones of each color. A "step" consists of exchanging positions of two adjacent stones. Find the smallest positive integer such that it is always possible to achieve, with at most steps, that the stones of each color remain followed if:
1. is even, 2. is odd and
~translated into English by Tomas Diaz. ~orders@tomasdiaz.com
Solution
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