/* * Created on 17.05.2004 * * This program implements the fast exponentiation.  *//** * @author Robert * * This is a class with static functions only. * fastExp implements the fast exponentiation.    */public class FastExp {	static int getCodingLength(int e) {		int k=0;		while ((1<<k)<e) ++k;		return k;	}		static int fastExp(int g, int e, int n) {		int l = getCodingLength(e);		int squares;		squares = g;		int result=1;		//successively compute squares and compute result		for (int k=0; k<l; ++k) {			if (((1<<k) & e)>0) {				result = (result*squares) % n;			}			squares = (squares*squares) % n;		}		//compute result 		return result;	}	public static void main(String[] args) {		System.out.println(fastExp(2, 20, 7));		System.out.println(fastExp(1234, 16912, 2345));		System.out.println(fastExp(1234, 541200, 2345));	}}