MathDB
2011 ToT Spring Junior O p1 numbers 1-2010 are placed along a circle

Source:

March 4, 2020
EvencombinatoricsDifference

Problem Statement

The numbers from 11 to 20102010 inclusive are placed along a circle so that if we move along the circle in clockwise order, they increase and decrease alternately. Prove that the difference between some two adjacent integers is even.