*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? (LCM of 1 to 20)*

https://projecteuler.net/problem=5

public class Euler5 { List> allFactors = new List

>(); List

finalFactors = new List (); public long Solve(int start, int end) { for (int i = start; i <= end; i++) { var factor = FindFactors(i); allFactors.Add(factor); } foreach (var factorsList in allFactors) { foreach (var factor in factorsList) { if (!finalFactors.Contains(factor)) finalFactors.Add(factor); int countCurrent = factorsList.Where(x => x == factor).Count(); while (countCurrent > finalFactors.Where(x => x == factor).Count()) { finalFactors.Add(factor); countCurrent--; } } } return finalFactors.Aggregate(1, (a, b) => a * b); } private List FindFactors(int num) { List result = new List (); while (num % 2 == 0) { result.Add(2); num /= 2; } int factor = 3; while (factor * factor <= num) { if (num % factor == 0) { result.Add(factor); num /= factor; } else factor += 2; } if (num > 1) result.Add(num); return result; } }