project Euler第三题

题目：The prime factors of 13195 are 5, 7, 13 and 29.What is the largest prime factor of the number 600851475143 ?算法：#!/usr/bin/env python#coding=utf-8a = 600851475143b = 0Li = 3Lwhil

shangzhihaohao

664人浏览 · 2011-11-05 21:12:39

shangzhihaohao · 2011-11-05 21:12:39 发布

题目：

The prime factors of 13195 are 5, 7, 13 and 29.

What is the largest prime factor of the number 600851475143 ?

算法：

#!/usr/bin/env python
#coding=utf-8

a = 600851475143
b = 0L
i = 3L
while i < a:
    i += 2
    if a%i == 0:
        a = a/i
        b = b if b>i else i
        i -= 2

print b

结果：

6857