Logo

Programming-Idioms

Compute the least common multiple x of big integers a and b. Use an integer type able to handle huge numbers.
New implementation

Be concise.

Be useful.

All contributions dictatorially edited by webmasters to match personal tastes.

Please do not paste any copyright violating material.

Please try to avoid dependencies to third-party libraries and frameworks.

Other implementations
#include <gmp.h>
mpz_t _a, _b, _x;
mpz_init_set_str(_a, "123456789", 10);
mpz_init_set_str(_b, "987654321", 10);
mpz_init(_x);

mpz_lcm(_x, _a, _b);
gmp_printf("%Zd\n", _x);
#include <numeric>
auto x = std::lcm(a, b);
int gcd(int a, int b)
{
  while (b != 0)
  {
    int t = b;
    b = a % t;
    a = t;
  }
  return a;
}

int lcm(int a, int b)
{
  if (a == 0 || b == 0)
    return 0;
  return (a * b) / gcd(a, b);
}

int x = lcm(140, 72);
import std.numeric: gcd
uint x = (a * b) / gcd(a, b);
x = lcm(a, b);

int lcm(int a, int b) => (a * b) ~/ gcd(a, b);

int gcd(int a, int b) {
  while (b != 0) {
    var t = b;
    b = a % t;
    a = t;
  }
  return a;
}
defmodule BasicMath do
	def gcd(a, 0), do: a
	def gcd(0, b), do: b
	def gcd(a, b), do: gcd(b, rem(a,b))
	
	def lcm(0, 0), do: 0
	def lcm(a, b), do: (a*b)/gcd(a,b)
end
gcd(A,B) when A == 0; B == 0 -> 0;
gcd(A,B) when A == B -> A;
gcd(A,B) when A > B -> gcd(A-B, B);
gcd(A,B) -> gcd(A, B-A).

lcm(A,B) -> (A*B) div gcd(A, B).
import "math/big"
gcd.GCD(nil, nil, a, b)
x.Div(a, gcd).Mul(x, b)
x = lcm a b
const gcd = (a, b) => b === 0 ? a : gcd (b, a % b)
let x = (a * b) / gcd(a, b)
import java.math.BigInteger;
BigInteger a = new BigInteger("123456789");
BigInteger b = new BigInteger("987654321");
BigInteger x = a.multiply(b).divide(a.gcd(b));
(setf x (lcm a b))
extension=gmp
$gcd = gmp_lcm($a, $b);
echo gmp_strval($gcd);
sub lcm {
	use integer;
	my ($x, $y) = @_;
	my ($f, $s) = @_;
	while ($f != $s) {
		($f, $s, $x, $y) = ($s, $f, $y, $x) if $f > $s;
		$f = $s / $x * $x;
		$f += $x if $f < $s;
	}
	$f
}
sub gcd {
	my ($x, $y) = @_;
	while ($x) { ($x, $y) = ($y % $x, $x) }
	$y
}
 
sub lcm {
	my ($x, $y) = @_;
	($x && $y) and $x / gcd($x, $y) * $y or 0
}
from math import gcd
x = (a*b)//gcd(a, b)
import math
x = math.lcm(a, b)
x = a.lcm(b)
extern crate num;

use num::Integer;
use num::bigint::BigInt;
let x = a.lcm(&b);