Hello CF!

I think many of you, in particular IOI participants, can not find a good, clear solutions of IOI problems, so I decided to create a blog where we will publish a problem then find solution for it and start to solve next problem (like on AOPS).

Let me begin — IOI 2006 B. Pyramid.

This page may be useful.

I know that I can I find solutions on this site but I think people have a lot of creative solutions for these problems.

Hello sir,thanks for the link :) But how to find questions of previous IOI's and their solution in this site

List of previous IOIs, click on a year to see the problems

Literally follow his link and click on the olympiad you want to check out, then follow the links (usually "The Competition")

Next task — IOI 2008 B. Islands.

Where can we test IOI problems , I mean is there any online link ?

Most of them are available on wcipeg

Also you can ask yeputons for an account on http://acm.math.spbu.ru/ . You can find there all IOI problems from 2003 up to 2014.