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51st Ukrainian National Mathematical Olympiad, 3rd Round

Ukraine counting and probability

Problem

Olesya writes down numbers at the vertices of a prism. After this, at each edge Andriy writes down the sum of numbers that are written at the vertices that form this edge. Can Olesya write numbers in such a way that all Andriy's numbers are different?
Solution
Yes. See fig. 10.
Final answer
Yes

Techniques

Coloring schemes, extremal argumentsOther