2022 Combo Div 2 P5
Source:
February 28, 2022
combinatorics
Problem Statement
Daniel, Ethan, and Zack are playing a multi-round game of Tetris. Whoever wins rounds first is crowned the champion. However Zack is trying to pull off a "reverse-sweep", where (at-least) one of the other two players first hits wins while Zack is still at , but Zack still ends up being the first to reach . How many possible sequences of round wins can lead to Zack pulling off a reverse sweep?Proposed by Dilhan Salgado