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.

https://projecteuler.net/problem=6

Brute Force

function sum(arr) {
  return arr.reduce(function(n, sum) { return sum + n; }, 0);
}

function square(n) {
  return Math.pow(n, 2);
}

function sumSquares(arr) {
  return sum(arr.map(square));
}

function squareSums(arr) {
  return square(sum(arr));
}

function euler6() {
  return squareSums(range(1,100)) - sumSquares(range(1,100));
}
timer(euler6);
// euler6 x 1: 0.078ms
// 25164150