romania tst
Source: Romania TST for IMO 1994 second exam
September 6, 2017
combinatoricsalgebra
Problem Statement
Let be a finite sequence of and . Under any two consecutive terms of this sequence is written if the digits are equal and is written otherwise. This way a new sequence of length is obtained.
By repeating this procedure times one obtains a triangular table of and . Find the maximum possible number of ones that can appear on this table