Does anyone know when Codechef snackdown t-shirt will arrive? I haven't received any email about it.

решение? "E" Угадай число https://www.russiancodecup.ru/en/tasks/round/6/E/

How to overcome contest failure and stay positive? It always hard for me to stay positive after i fail something(lose rating,lower grades than my friends,...)

I don't understand why in some dp problems dp[0] is equal to 0,like the coin change problem.Can someone explain this to me?