Smallest Multiple

// https://projecteuler.net/problem=5

// 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?

// Answer: 232792560

#include <iostream>
#include <cstdint>

int prob005_brute_force(int max)
{
  uint32_t answer = 0;
  uint32_t test = max;
  bool check = false;
  while (!check) {
    check = true;
    for( uint32_t i = max ; i && check ; --i){
      check &= (0 == (test%i));
    }
    if( !check ){
      test += 20;
    }
  }
  answer = test;
  return answer;
}

#if ! defined UNITTEST_MODE
int main(int argc, char const *argv[])
{
  std::cout << "Answer: " << prob005_brute_force(20) << std::endl;
}
#endif

package org.tvarley.euler.solutions;

import org.tvarley.euler.Solution;

public class Solution005 implements Solution {
  public String solve() {
    int lcm = 1;
    for (int i = 2; i <= 20; i++) {
      lcm = lcm(lcm, i);
    }
    return Integer.toString(lcm);
  }

  private int lcm(int a, int b) {
    return a * (b / gcd(a, b));
  }

  private int gcd(int a, int b) {
    while (b != 0) {
      int t = b;
      b = a % b;
      a = t;
    }
    return a;
  }
}

module.exports = {
  answer : () => {
    var answer = 0;
    var test = 20;
    var check = false;

    while( !check ) {
      check = true;
      for( i = 20 ; i && check ; --i ) {
        check &= (0 == (test % i));
      }
      if( !check ) {
        test += 20;
      }
    }
    return test;
  }
};

def solve():
    """
    Smallest multiple
    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?
    """
    from math import gcd
    lcm = 1
    for i in range(1, 21):
        lcm = lcm * i // gcd(lcm, i)
    return lcm

def will_divide(test_me)
  20.downto(1) do |i|
    return false if test_me % i != 0
  end
  true
end

def euler005_solution
  answer = 20
  loop do
    break if will_divide(answer)

    answer += 20
  end
  answer
end

puts euler005_solution if __FILE__ == $PROGRAM_NAME

package main

import "fmt"

func gcd(a, b int64) int64 {

    for b != 0 {

        a, b = b, a%b

    }

    return a

}

func lcm(a, b int64) int64 {

    return a / gcd(a, b) * b

}

func main() {

    n := int64(1)

    for i := int64(2); i <= 20; i++ {

        n = lcm(n, i)

    }

    fmt.Println(n)

}

// https://projecteuler.net/problem=5

// 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?

// Answer: 232792560

pub fn prob005_brute_force(max: u32) -> u32
{
    let mut test = max;
    let mut check = false;

    while !check {
        check = true;
        for i in 1..max {
            check = 0 == (test % i);
            if !check {
                break;
            };
        }
        if !check {
            test += 20;
        }
    }
    return test;
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn euler_005() {
        assert_eq!(prob005_brute_force(20), 232_792_560);
    }
}