Hi,

Are the practice tasks for IOI 2016 available anywhere? I can't seem to find them.

Thanks :)

Hi,

IOI website (http://ioinformatics.org/) seems to be down from here. Is anyone experiencing the same issue? Is there any way to alert the admins of the site about this?

UPD: Seems that it's up again.

Thanks!

Hi everyone,

I've asked myself many times why I am doing and why I like competitive programming.

Now I'd like to invite everyone to answer this same question.

Why are you doing competitive programming and why do you like it?

Hi Codeforces,

I'm going to IOI this year and I'm currently preparing for it. My teammates have recommended this site to me and I have registered here today. This site looks great so far :)

Anyway, back to the original topic. As graph theory is an important component in IOI, I'm currently preparing hard for it. I know that direct implementations of the standard graph algorithms will not be tested in IOI, so I'm trying to think of variations and applications of some standard algorithms. I have thought of these so far for MST and Dijkstra.

• MST

• Find number of unique MST

• Find MST that doesn't use a certain edge/certain edges
• Minimum Spanning Forest
• Second best spanning tree

• Dijkstra

• Find number of shortest paths
• Find shortest path with minimum/maximum/certain number of edges for a weighted graph
• Find shortest path that passes through a certain vertex/certain vertices/a certain edge/certain edges
• Second best shortest path

I would really appreciate it if anyone can help provide descriptions of possible solutions for the above variations. I would also appreciate it if anyone can state more variations of the common algorithms(not just these two) that I have not listed above.

Thank you!~