UVa 100 - The 3n + 1 problem, https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=3&page=show_problem&problem=36

uva-100.java

import java.io.PrintWriter;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws Exception {
		new Main().go();
	}

	private void go() {
		Scanner in = new Scanner(System.in);
		PrintWriter out = new PrintWriter(System.out, true);

		while (in.hasNextInt()) {
			int max = 0;
			int s = in.nextInt();
			int e = in.nextInt();

			for (int i = Math.min(s, e); i <= Math.max(s, e); i++) {
				int n = i;
				int count = 0;
				while (n != 1) {
					n = (n % 2 == 1) ? 3 * n + 1 : n / 2;
					++count;
				}
				++count;
				if (count > max)
					max = count;
			}
			out.printf("%d %d %d\n", s, e, max);
		}
	}
}