Algorithm: Related to Divisors

divisors.py

"""
Additional Info

- 제곱수(1, 4, 9, 16, 25, 100, 121, ...)의 약수의 갯수는 항상 홀수이다.
"""


__all__ = ['get_divisors', 'get_n_divisors']


def get_divisors(num: int) -> list:
    divisors = []
    for i in range(1, int(num**(1/2))+1):
        if num % i == 0:
            pair = num // i
            if i != pair:
                divisors.extend([i, pair])
            else:
                divisors.append(i)
    
    divisors.sort()
    return divisors


def get_n_divisors(num: int) -> int:
    n_divisors = 0
    for i in range(1, int(num**(1/2))+1):
        if num % i == 0:
            n_divisors += 2
        if num // i == i:  # num // i == pair
            n_divisors -= 1
    return n_divisors