Python/project_euler/problem_06/sol4.py
Dhruv ddf83ec886
Add default arguments for Project Euler problem 6 (#2957)
- Add default arguments to solution function
- Add link to Project Euler problem 6
- Add doctest for testing `solution()`
- Removed test_solutions.py as it is redundant
2020-10-07 10:17:43 +05:30

43 lines
1.1 KiB
Python
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

"""
Problem 6: https://projecteuler.net/problem=6
The sum of the squares of the first ten natural numbers is,
1^2 + 2^2 + ... + 10^2 = 385
The square of the sum of the first ten natural numbers is,
(1 + 2 + ... + 10)^2 = 552 = 3025
Hence the difference between the sum of the squares of the first ten natural
numbers and the square of the sum is 3025 385 = 2640.
Find the difference between the sum of the squares of the first N natural
numbers and the square of the sum.
"""
def solution(n: int = 100) -> int:
"""Returns the difference between the sum of the squares of the first n
natural numbers and the square of the sum.
>>> solution(10)
2640
>>> solution(15)
13160
>>> solution(20)
41230
>>> solution(50)
1582700
>>> solution()
25164150
"""
sum_of_squares = n * (n + 1) * (2 * n + 1) / 6
square_of_sum = (n * (n + 1) / 2) ** 2
return int(square_of_sum - sum_of_squares)
if __name__ == "__main__":
import doctest
doctest.testmod()
print(solution(int(input("Enter a number: ").strip())))