curriculum/challenges/english/blocks/rosetta-code-challenges/5a23c84252665b21eecc7edf.md
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 <a href="https://rosettacode.org/wiki/Greatest_common_divisor" target="_blank" rel="noopener noreferrer nofollow">greatest common divisor</a>, then this formula calculates $lcm$.
$$ \operatorname{lcm}(m, n) = \frac{|m \times n|}{\operatorname{gcd}(m, n)} $$
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.
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);
function LCM(A) {
}
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;
}