MathDB

C4

Part of 2017-IMOC

Problems(1)

no neighbors with consecutive heights

Source: IMOC 2017 C4

8/12/2021
There are 3N+13N+1 students with different heights line up for asking questions. Prove that the teacher can drive 2N2N students away such that the remain students satisfies: No one has neighbors whose heights are consecutive.
combinatorics