check out http://www.codechef.com/DINP1501/ it has mock INOI_____. these may help 
The questions were very easy but nice…I solved all of them but did not get a good rank (I ranked 88) since I started only 3.5 hours before the end time (when I saw this post).
True, but I got WA on CHEFARR all because I used the wrong datatype. I thought 5*10^5 would fit in int as it had worked in many other problems.