HackerRank helper (math) functions

HackerRank - Helpers

/**
 * Fast modular exponentiation for i ^ n % modulus
 * Used when exp is a extremely large number, ie: Math.pow(2, 400);
 * @returns {number}
 */
function fastModularExponentiation(i, n, modulus) {
  if (modulus == 1) return 0;

  var c = 1;
  for (var e = 1; e <= n; e++) {
    c = (c * i) % modulus;
  }

  return c;
}