Does anyone know of problems which have solutions similar to that of IOI 2014 Friend where you try to use something like Induction.
For example in that problem, we try to remove each node and changing the remaining graph somehow so that the answer doesn't change.
One example I know is: http://main.edu.pl/en/archive/oi/12/dwa
Does anyone know of any other problems?
Looks like 549B - Looksery Party is what you're looking for.
Off-topic: does the task name change if one change the site language? I am having the task name "Вечеринка в Looksery" in both english and russian versions.