I stress tested a few of the other participants codes of today's educational and found a few cases where they fail. But the input size is around ~2 MB where the maximum allowed limit is 256 KB. SO i can't upload it. Can't this size limit be removed for educational rounds?

I simply suck at combinatorics and probability problems. So I decided that I'll finish reading a book on each of these topics in 2017. Which book should i choose?