素因数分解 (MicroPython)

#
#   素因数分解
#
import utime

def prime_factorize(n):
    a = []
    while n % 2 == 0:
        a.append(2)
        n //= 2
    f = 3
    while f * f <= n:
        if n % f == 0:
            a.append(f)
            n //= f
        else:
            f += 2
    if n != 1:
        a.append(n)
    return a


if __name__ == '__main__':
    start_time = utime.ticks_ms()
#   CircuitPythonの場合
#    start_time = time.monotonic_ns() // 1000000

    a = prime_factorize(849374738754534871)

    end_time = utime.ticks_ms()
#   CircuitPythonの場合
#    end_time = time.monotonic_ns() // 1000000

    print(a)
    print("{0:.3f} 秒".format((end_time - start_time) / 1000.0))