mirror of
https://github.com/TheAlgorithms/Python.git
synced 2024-11-24 13:31:07 +00:00
98e9d6bdb6
* Fix style of the first ten solutions for Project Euler - Unify the header docstring, and add reference URLs to wikipedia or similar - Fix docstrings to be properly multilined - Add newlines where appropriate - Add doctests where they were missing - Remove doctests that test for the correct solution - fix obvious spelling or grammar mistakes in comments and exception messages - Fix line endings to be UNIX. This makes two of the files seem to have changed completely - no functional changes in any of the solutions were done (except for the spelling fixes mentioned above) * Fix docstrings and main function as per Style Guide
73 lines
1.9 KiB
Python
73 lines
1.9 KiB
Python
"""
|
|
Project Euler Problem 2: https://projecteuler.net/problem=2
|
|
|
|
Even Fibonacci Numbers
|
|
|
|
Each new term in the Fibonacci sequence is generated by adding the previous
|
|
two terms. By starting with 1 and 2, the first 10 terms will be:
|
|
|
|
1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ...
|
|
|
|
By considering the terms in the Fibonacci sequence whose values do not exceed
|
|
four million, find the sum of the even-valued terms.
|
|
|
|
References:
|
|
- https://en.wikipedia.org/wiki/Fibonacci_number
|
|
"""
|
|
import math
|
|
from decimal import Decimal, getcontext
|
|
|
|
|
|
def solution(n: int = 4000000) -> int:
|
|
"""
|
|
Returns the sum of all even fibonacci sequence elements that are lower
|
|
or equal to n.
|
|
|
|
>>> solution(10)
|
|
10
|
|
>>> solution(15)
|
|
10
|
|
>>> solution(2)
|
|
2
|
|
>>> solution(1)
|
|
0
|
|
>>> solution(34)
|
|
44
|
|
>>> solution(3.4)
|
|
2
|
|
>>> solution(0)
|
|
Traceback (most recent call last):
|
|
...
|
|
ValueError: Parameter n must be greater than or equal to one.
|
|
>>> solution(-17)
|
|
Traceback (most recent call last):
|
|
...
|
|
ValueError: Parameter n must be greater than or equal to one.
|
|
>>> solution([])
|
|
Traceback (most recent call last):
|
|
...
|
|
TypeError: Parameter n must be int or castable to int.
|
|
>>> solution("asd")
|
|
Traceback (most recent call last):
|
|
...
|
|
TypeError: Parameter n must be int or castable to int.
|
|
"""
|
|
|
|
try:
|
|
n = int(n)
|
|
except (TypeError, ValueError):
|
|
raise TypeError("Parameter n must be int or castable to int.")
|
|
if n <= 0:
|
|
raise ValueError("Parameter n must be greater than or equal to one.")
|
|
getcontext().prec = 100
|
|
phi = (Decimal(5) ** Decimal(0.5) + 1) / Decimal(2)
|
|
|
|
index = (math.floor(math.log(n * (phi + 2), phi) - 1) // 3) * 3 + 2
|
|
num = Decimal(round(phi ** Decimal(index + 1))) / (phi + 2)
|
|
total = num // 2
|
|
return int(total)
|
|
|
|
|
|
if __name__ == "__main__":
|
|
print(f"{solution() = }")
|