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MathNet 2006 — Part 04 Question 134

Math Olympiad Vault · MathNet 2006 — Part 04

Question 134

Mariyka has drawn a square grid $2006 \times 2006$ on a blackboard. During one step, it is allowed to choose any unit segment of that grid and erase it together with all adjacent segments, which were not erased before (so, at most $7$ segments can be erased in one step). Is it possible to erase the whole drawing in no more than $1300000$ steps?