Choice of programming language doesn't matter much in competitive programming. Say, Pascal (or sometimes Delphi dialect of it) is historically very popular in

Choice of programming language doesn't matter much in competitive programming. Say, Pascal (or sometimes Delphi dialect of it) is historically very popular in Russia / Belarus, it's still a primary language in schools. However, lots of student teams participating in ACM ICPC moved to Java just because it has more data structures in its standard library and it can handle bignums out of the box, meaning you have more time to think about solutions instead of coding long division.