Write fib(n) returning the n-th Fibonacci number with fib(0) = 0, fib(1) = 1. It must be fast for n up to 80.
fib(10) → 55
fib(0) → 0
Submit runs 6 tests, including hidden edge cases.
Each hint gives a little more help. Try on your own first.
Run your code to see the output here.