MPhil Mathematics (admission)

Hello,

[sorry for writing too long]

I got my bachelor degree in CS here in India with a low gpa (7.2/10), I want to apply for MPhil (mathematics). Should I contact some professor first?

[I know its out of context but if you have any idea please entertain this too]

I have a low GPA but apart from this I have given numerous algorithmic coding contests online and got some decent ranks in them , I was also qualified for ACM-ICPC regionals (Olympics of algorithmic programming), qualified two rounds of Facebook hacker cup and one round of google code jam and recently got a descent rank in Quant championship by WorldQuant. Do I have any chance?