MathDB
2012 ToT Fall Senior A p7 1 000 000$ soldiers in a line

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March 22, 2020
combinatorics

Problem Statement

There are 10000001 000 000 soldiers in a line. The sergeant splits the line into 100100 segments (the length of different segments may be different) and permutes the segments (not changing the order of soldiers in each segment) forming a new line. The sergeant repeats this procedure several times (splits the new line in segments of the same lengths and permutes them in exactly the same way as the first time). Every soldier originally from the first segment recorded the number of performed procedures that took him to return to the first segment for the first time. Prove that at most 100100 of these numbers are different.