30-second algorithm to check if a number is prime

At coding competitions time is very important and so is knowing whether a number is prime or not. Here's an algorithm that tests if a number is prime that you can implement in less than 30 seconds.

[teodoremanueltarcavu]

Holy smokes, that was some fast coding skill example. Thank you!

[CodeChrisB]

What If we Want to Check extreme big Numbers way beyond Int max or even Long max for example 2^99-1