pre-commit-ci[bot] edf7c372a9
[pre-commit.ci] pre-commit autoupdate ()
* [pre-commit.ci] pre-commit autoupdate

updates:
- [github.com/astral-sh/ruff-pre-commit: v0.9.10 → v0.11.0](https://github.com/astral-sh/ruff-pre-commit/compare/v0.9.10...v0.11.0)
- [github.com/abravalheri/validate-pyproject: v0.23 → v0.24](https://github.com/abravalheri/validate-pyproject/compare/v0.23...v0.24)

* Fix ruff issues

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Christian Clauss <cclauss@me.com>
2025-03-18 09:53:49 +01:00

59 lines
1.2 KiB
Python

"""
Problem 28
Url: https://projecteuler.net/problem=28
Statement:
Starting with the number 1 and moving to the right in a clockwise direction a 5
by 5 spiral is formed as follows:
21 22 23 24 25
20 7 8 9 10
19 6 1 2 11
18 5 4 3 12
17 16 15 14 13
It can be verified that the sum of the numbers on the diagonals is 101.
What is the sum of the numbers on the diagonals in a 1001 by 1001 spiral formed
in the same way?
"""
from math import ceil
def solution(n: int = 1001) -> int:
"""Returns the sum of the numbers on the diagonals in a n by n spiral
formed in the same way.
>>> solution(1001)
669171001
>>> solution(500)
82959497
>>> solution(100)
651897
>>> solution(50)
79697
>>> solution(10)
537
"""
total = 1
for i in range(1, ceil(n / 2.0)):
odd = 2 * i + 1
even = 2 * i
total = total + 4 * odd**2 - 6 * even
return total
if __name__ == "__main__":
import sys
if len(sys.argv) == 1:
print(solution())
else:
try:
n = int(sys.argv[1])
print(solution(n))
except ValueError:
print("Invalid entry - please enter a number")