Project Euler #25

euler-25.py

def fib():
    first = 0 
    second = 1
    while True:
        cached = first
        first = first + second
        second = cached
        yield first


def main():
    for index, current in enumerate(fib()):
        if len(str(current)) >= 1000:
            answer = index + 1
            break
    print(answer)

if __name__ == '__main__':
    main()

$ time python euler-25.py
4782

real 0m0.069s
user 0m0.060s
sys 0m0.008s