freeCodeCamp/curriculum/challenges/english/10-coding-interview-prep/rosetta-code/least-common-multiple.md

id, title, challengeType, forumTopicId, dashedName

id	title	challengeType	forumTopicId	dashedName
5a23c84252665b21eecc7edf	Least common multiple	5	302301	least-common-multiple

--description--

The least common multiple of 12 and 18 is 36, because 12 is a factor (12 × 3 = 36), and 18 is a factor (18 × 2 = 36), and there is no positive integer less than 36 that has both factors. As a special case, if either m or n is zero, then the least common multiple is zero. One way to calculate the least common multiple is to iterate all the multiples of m, until you find one that is also a multiple of n. If you already have gcd for greatest common divisor, then this formula calculates lcm. ( \operatorname{lcm}(m, n) = \frac{|m \times n|}{\operatorname{gcd}(m, n)} )

--instructions--

Compute the least common multiple of an array of integers. Given m and n, the least common multiple is the smallest positive integer that has both m and n as factors.

--hints--

LCM should be a function.

assert(typeof LCM == 'function');

LCM([2, 4, 8]) should return a number.

assert(typeof LCM([2, 4, 8]) == 'number');

LCM([2, 4, 8]) should return 8.

assert.equal(LCM([2, 4, 8]), 8);

LCM([4, 8, 12]) should return 24.

assert.equal(LCM([4, 8, 12]), 24);

LCM([3, 4, 5, 12, 40]) should return 120.

assert.equal(LCM([3, 4, 5, 12, 40]), 120);

LCM([11, 33, 90]) should return 990.

assert.equal(LCM([11, 33, 90]), 990);

LCM([-50, 25, -45, -18, 90, 447]) should return 67050.

assert.equal(LCM([-50, 25, -45, -18, 90, 447]), 67050);

--seed--

--seed-contents--

function LCM(A) {

}

--solutions--

function LCM(A) {
  var n = A.length,
    a = Math.abs(A[0]);
  for (var i = 1; i < n; i++) {
    var b = Math.abs(A[i]),
      c = a;
    while (a && b) {
      a > b ? (a %= b) : (b %= a);
    }
    a = Math.abs(c * A[i]) / (a + b);
  }
  return a;
}