30-seconds-of-code/snippets/js/s/lcm.md

title, type, language, tags, cover, dateModified

title	type	language	tags	cover	dateModified
Least common multiple	snippet	javascript	math algorithm recursion	waving-over-lake	2020-12-28T13:49:24+02:00

Calculates the least common multiple of two or more numbers.

• Use the greatest common divisor (GCD) formula and the fact that lcm(x, y) = x * y / gcd(x, y) to determine the least common multiple.
• The GCD formula uses recursion.

const lcm = (...arr) => {
  const gcd = (x, y) => (!y ? x : gcd(y, x % y));
  const _lcm = (x, y) => (x * y) / gcd(x, y);
  return [...arr].reduce((a, b) => _lcm(a, b));
};

lcm(12, 7); // 84
lcm(...[1, 3, 4, 5]); // 60