ProjectEuler6

2017/10/28

  • 問題

Problem 6:Sum square difference
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 = 55^2 = 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 one hundred natural numbers and the square of the sum.

  • 解答例
num = 100

mul1 = num * (num + 1) * (2 * num + 1) // 6
mul2 = (num * (num + 1) // 2) ** 2

print(mul2 - mul1)