algorithm-in-python/math/numberTheory/factor.py
2019-01-31 12:09:46 +08:00

54 lines
1.3 KiB
Python

#coding: utf-8
''' mbinary
#######################################################################
# File : factorize.py
# Author: mbinary
# Mail: zhuheqin1@gmail.com
# Blog: https://mbinary.xyz
# Github: https://github.com/mbinary
# Created Time: 2018-12-16 09:36
# Description: factorization, using pollard's rho algorithm and miller-rabin primality test
#######################################################################
'''
from random import randint
from isPrime import isPrime
from gcd import gcd
def factor(n):
'''pollard's rho algorithm'''
if n<1:raise Exception('[Error]: {} is less than 1'.format(n))
if n==1: return []
if isPrime(n):return [n]
fact=1
cycle_size=2
x = x_fixed = 2
c = randint(1,n)
while fact==1:
for i in range(cycle_size):
if fact>1:break
x=(x*x+c)%n
if x==x_fixed:
c = randint(1,n)
continue
fact = gcd(x-x_fixed,n)
cycle_size *=2
x_fixed = x
return factor(fact)+factor(n//fact)
def fact(n):
f=2
ret = []
while f*f<=n:
while not n%f:
ret.append(f)
n//f
f+=1
if n>1:ret.append(n)
return ret
if __name__=='__main__':
while 1:
n = int(input('n: '))
print(factor(n))