Python/project_euler/problem_33/sol1.py
Dhruv 501a2ff430
[Project Euler] Fix code style for multiple problems (#3094)
* Fix code style for Project Euler problems:

- 13, 17, 21
- Default args
- Type hints
- File path

* Fix code style for multiple problems

* Made suggested changes
2020-10-10 21:23:17 +05:30

69 lines
1.9 KiB
Python

"""
Problem 33: https://projecteuler.net/problem=33
The fraction 49/98 is a curious fraction, as an inexperienced
mathematician in attempting to simplify it may incorrectly believe
that 49/98 = 4/8, which is correct, is obtained by cancelling the 9s.
We shall consider fractions like, 30/50 = 3/5, to be trivial examples.
There are exactly four non-trivial examples of this type of fraction,
less than one in value, and containing two digits in the numerator
and denominator.
If the product of these four fractions is given in its lowest common
terms, find the value of the denominator.
"""
from fractions import Fraction
from typing import List
def is_digit_cancelling(num: int, den: int) -> bool:
if num != den:
if num % 10 == den // 10:
if (num // 10) / (den % 10) == num / den:
return True
return False
def fraction_list(digit_len: int) -> List[str]:
"""
>>> fraction_list(2)
['16/64', '19/95', '26/65', '49/98']
>>> fraction_list(3)
['16/64', '19/95', '26/65', '49/98']
>>> fraction_list(4)
['16/64', '19/95', '26/65', '49/98']
>>> fraction_list(0)
[]
>>> fraction_list(5)
['16/64', '19/95', '26/65', '49/98']
"""
solutions = []
den = 11
last_digit = int("1" + "0" * digit_len)
for num in range(den, last_digit):
while den <= 99:
if (num != den) and (num % 10 == den // 10) and (den % 10 != 0):
if is_digit_cancelling(num, den):
solutions.append(f"{num}/{den}")
den += 1
num += 1
den = 10
return solutions
def solution(n: int = 2) -> int:
"""
Return the solution to the problem
"""
result = 1.0
for fraction in fraction_list(n):
frac = Fraction(fraction)
result *= frac.denominator / frac.numerator
return int(result)
if __name__ == "__main__":
print(solution())