SMO 2015 open q2
Source: SMO 2015 open, 2nd round
March 31, 2018
graph theorySequences
Problem Statement
A boy lives in a small island in which there are three roads at every junction. He starts
from his home and walks along the roads. At each junction he would choose to turn
to the road on his right or left alternatively, i.e., his choices would be . . ., left, right,
left,... Prove that he will eventually return to his home.