Guys i have just found a page that i would like to share it is called hackertyper.net and it is real fun! Watch me demonstrating here https://www.youtube.com/watch?v=uvXitQGQKIY . Hope you liked it!

Can anybody explain me how to find the second minimum spanning tree in the fastest way, I heard about disjoint sets I studied them but I still can't find the way to do it...

Does anyone know which is the algorithm for country ratings?