module Euler5

// 2520 is the smallest number that can be divided by each of the numbers from 1 to 10 without any remainder.
// What is the smallest positive number that is evenly divisible by all of the numbers from 1 to 20?

imports
  Prelude
  Data.Stack

where

main :: () -> I32
main () = do
  i = new 1
  while (not (all_20 @i)) (inc i)
  putW @i
  assert (@i == 232792560)
  0

is_factor :: { Arith a, Eq a } => a -> a -> Bool
is_factor x y => (x % y) == 0

all_20 :: W32 -> Bool
all_20 x = do
  b = new True
  for 1 (\i -> (i <= 20) && @b) succ
    (\i -> b <- is_factor x i)
  @b