Python/project_euler/problem_026/sol1.py

61 lines
1.5 KiB
Python
Raw Normal View History

"""
Euler Problem 26
https://projecteuler.net/problem=26
Problem Statement:
A unit fraction contains 1 in the numerator. The decimal representation of the
unit fractions with denominators 2 to 10 are given:
1/2 = 0.5
1/3 = 0.(3)
1/4 = 0.25
1/5 = 0.2
1/6 = 0.1(6)
1/7 = 0.(142857)
1/8 = 0.125
1/9 = 0.(1)
1/10 = 0.1
Where 0.1(6) means 0.166666..., and has a 1-digit recurring cycle. It can be
seen that 1/7 has a 6-digit recurring cycle.
Find the value of d < 1000 for which 1/d contains the longest recurring cycle
in its decimal fraction part.
"""
def solution(numerator: int = 1, digit: int = 1000) -> int:
"""
Considering any range can be provided,
because as per the problem, the digit d < 1000
>>> solution(1, 10)
7
>>> solution(10, 100)
97
>>> solution(10, 1000)
983
"""
the_digit = 1
longest_list_length = 0
for divide_by_number in range(numerator, digit + 1):
has_been_divided: list[int] = []
now_divide = numerator
for division_cycle in range(1, digit + 1):
if now_divide in has_been_divided:
if longest_list_length < len(has_been_divided):
longest_list_length = len(has_been_divided)
the_digit = divide_by_number
else:
has_been_divided.append(now_divide)
now_divide = now_divide * 10 % divide_by_number
return the_digit
# Tests
if __name__ == "__main__":
import doctest
doctest.testmod()