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Update prime_factorization_fast.py

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Removing recursion, using while loops
Better variable names
List default argument is removed from function
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Sourabh kumar verma 2023-08-06 20:48:25 +05:30 committed by GitHub
parent 4eb7f1d548
commit 2590a893f8
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1 changed files with 37 additions and 34 deletions
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maths/prime_factorization_fast.py
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@ -1,57 +1,60 @@
from math import ceil, sqrt
from __future__ import annotations
from math import ceil , sqrt
def primeproduct( num : int) -> list[int]:
def primeproduct(n: int, x: list = []) -> list[int]:
"""
'''
>>> primeproduct(868)
[2, 2, 7, 31]
>>> primeproduct(9039423423423743)
[2, 2, 7, 31, 719, 12572216166097]
>>> primeproduct(0.02)
Traceback (most recent call last):
ValueError: invalid literal for int() with base 10: '0.02'
>>> primeproduct(-2342)
[]
"""
if n < 1:
'''
if num <= 1:
return []
if n > 1:
if len(x) >= 1 and x[-1] % n == 0: # check in already factorised
x.append(x[-1])
n = n // x[-1]
prime_factors = []
while num > 1:
if len(prime_factors) >= 1 and prime_factors[-1] % num ==0:
prime_factors.append(prime_factors[-1])
else:
sq = ceil(sqrt(n))
sq = ceil(sqrt(num))
flag = 0
if x != []:
for i in range(x[-1], sq + 1, 2):
if n % i == 0:
n = n // i
x.append(i)
if prime_factors!=[]:
for i in range(prime_factors[-1], sq+1 , 2):
if num % i == 0:
num = num // i
prime_factors.append(i)
flag = 1
break
else:
# Handle factor 2 separately
while n % 2 == 0: # only 2 is even prime
n = n // 2
x.append(2)
while num % 2 == 0:
num = num // 2
prime_factors.append(2)
# Start loop from 3 and increment by 2
for i in range(3, sq + 1, 2): # skip even numbers
if n % i == 0:
n = n // i
x.append(i)
for i in range(3 , sq+1 , 2):
if num % i == 0:
num = num // i
prime_factors.append(i)
flag = 1
break
if not flag:
x.append(n)
n = 1
return primeproduct(n, x)
if not flag and num > 1:
prime_factors.append(num)
num = 1
break
return x
return prime_factors
# faster than https://github.com/sourabhkv/Python/blob/master/maths/prime_factors.py approx 2x