Euler P14.java

public void p14() {
	int max = 0;

	for (int i = 1000000; i > 0; i--) {
		int c = collatz((long)i,2);

		if (c > max) {
			max = c;
		}
	}

	System.out.println(max);
}

public int collatz(long n, int c) {
	if (n % 2L == 0L) {
		n = n / 2L;
	} else {
		n = (3L * n) + 1L;
	}

	if (n == 1) { 
		return c;
	}

	return collatz(n, c + 1);
}