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

title, tags

title	tags
lcm	math,list,recursion,advanced

Returns the least common multiple of two or more numbers.

Define a function, spread, that uses either list.extend() or list.append() on each element in a list to flatten it. Use math.gcd() and lcm(x,y) = x * y / gcd(x,y) to determine the least common multiple.

from functools import reduce
import math

def spread(arg):
  ret = []
  for i in arg:
    if isinstance(i, list):
      ret.extend(i)
    else:
      ret.append(i)
  return ret

def lcm(*args):
  numbers = []
  numbers.extend(spread(list(args)))

  def _lcm(x, y):
    return int(x * y / math.gcd(x, y))

  return reduce((lambda x, y: _lcm(x, y)), numbers)

lcm(12, 7) # 84
lcm([1, 3, 4], 5) # 60