I am currently preparing for IOI. I have a strong math background ( I almost made it to IMO last year and can solve many of the ISL C 4+). I have my IOI TSTs in about $$$1 \frac{1}{2}$$$ months. Since I have so less time, how should I prepare? How should I practice for IOI? Also, since very little time is left, I would want to not waste time in things out of syllabus. From where should I practice different algorithms and data structures? ( I often have problems implementing data structures.)