006 Sum square difference.sf

#!/usr/bin/ruby

# Author: Daniel "Trizen" Șuteu
# License: GPLv3
# Website: https://github.com/trizen

# Find the difference between the sum of the squares of the first one hundred natural numbers and the square of the sum.

# https://projecteuler.net/problem=6

# Runtime: 0.148s

func sum_pow_2(n) {
    1/3 * [n**3, (3/2)*(n**2), (1/2)*n].sum;
}

func sum_pow_1(n) {
    1/2 * [n**2, n].sum;
}

say int(sum_pow_1(100)**2 - sum_pow_2(100));