KöMaL 2018 K585

Andrew wrote three (not necessarily different) positive integers on a blackboard, each of them smaller than $2018$. Then he erased these numbers ($A$, $B$ and $C$), and replaced them with $\frac{A+B}2, \frac{B+C}2, \frac{A+C}2.$ He repeated this procedure $11$ times altogether. As a result, one of the three numbers on the board is $100$. What are the other two numbers?