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PrintSelection and Training Session
Belarus counting and probability
Problem
We call a coloring of an table () in three colors a good coloring if the following two conditions are satisfied:
1) Each cell has the same number of neighboring cells of two other colors; 2) Each corner cell has no neighboring cells of its color.
Find all pairs () for which there exists a good coloring of table.
1) Each cell has the same number of neighboring cells of two other colors; 2) Each corner cell has no neighboring cells of its color.
Find all pairs () for which there exists a good coloring of table.
Solution
Answer: all such that divides both of them.
Final answer
All pairs where both dimensions are multiples of six.
Techniques
Coloring schemes, extremal argumentsInvariants / monovariants