Java: Smallest Multiple

This post is made gathering data from other nice sites, but just wanted to have it in a common place.

This is the solution for Project Euler, question #5: Smallest Number.

	public class MyClass {
	public static void main(String args[]) {
	System.out.println(findSmallestMultiple(20));
	}
	/* returns smallest multiple that is evenly divisible by all numbers from 1 - n
	* returns -1 if multiple does not exist
	* works up to n = 20 (long reaches maximum value for values > 20) */
	public static long findSmallestMultiple(int n) {
	for (long i = n; i <= factorial(n); i += n) {
	if (isMultiple(i, n)) {
	return i;
	}
	}
	return -1;
	}
	/* checks every number between 1 and n to see if x is a multiple of every number
	* returns true if x is found to be a multiple of every number, and false if x is
	* found to not be a multiple of any number */
	public static boolean isMultiple(long x, int n) {
	for (int i = 1; i < n; i++) {
	if (x % i != 0) {
	return false;
	}
	}
	return true;
	}
	/* returns the n factorial, or -1 if it does not exist; works up to 20 */
	public static long factorial (long n) {
	if (n > 1) {
	return n * factorial(n - 1);
	}
	else if (n >= 0) {
	return 1;
	}
	else {
	return -1;
	}
	}
	}

view raw SmallestMultiple.java hosted with ❤ by GitHub