Desarrollo de Aplicaciones Web

import java.util.Scanner;

class NumerLychrel {
	private int count = 0;
	private long valor;

public NumerLychrel(long valor) {
	this.valor = lichrel(valor, count);
}

private long lichrel(long valor, int count) {
	long numberReversed = 0;
	for (long i = valor; i != 0; i /= 10) {
		numberReversed = numberReversed * 10 + i % 10;
	}
	if ((valor == numberReversed && count > 0)) {
		this.count = count;
		return valor;
	} else {
		if(valor > 1000000000){
			return valor;
		}else{
			count++;
			return lichrel(valor + numberReversed, count);
		}
	}

}

public long getValor() {
	return this.valor;
}
public int getCount() {
	return this.count;
}
}

public class NumerLychrelTester {
	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		NumerLychrel lich;
		int numCasos;
		numCasos = in.nextInt();
		long valor;
		int count = 0;
		for (int i = 0; i < numCasos; i++) {
			valor = in.nextInt();
			lich = new NumerLychrel(valor);
			if (lich.getValor() >= 1000000000) {
				System.out.println("Lychrel?");
			} else {
				System.out.println(lich.getCount() + " " + lich.getValor());
			}
		}

}
}

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
//import java.util.Scanner;

public class ConstanteMagica {

public static void main(String[] args) throws IOException {
	BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
	// Scanner in = new Scanner(System.in);
	String[] nums = in.readLine().split(" ");
	int n = Integer.valueOf(nums[0]);
	int num = Integer.valueOf(nums[1]);
	
	while (n != 0 || num != 0) {
		// 9 4 5
		System.out.println(((n * n) / 2 + num) * n);
		nums = in.readLine().split(" ");
		n = Integer.valueOf(nums[0]);
		num = Integer.valueOf(nums[1]);
	}
	in.close();
}
}

import java.util.Scanner;

class PrimaDeRiesgo {
	
int calcPrimaRiesgo(String valor1, int index, int result) {
	
	if (index == 0) {
		return result;
	} else {
		char character = valor1.charAt(index-1);
		int ascii = (int) character;
		return calcPrimaRiesgo(valor1, index-1, result + ascii);
	}
}
int isPrime(int numero) {
    for(int i=2;i<numero;i++) {
        if(numero%i==0)
            return isPrime(numero-1);
    }
    return numero;
}

}
public class PrimaDeRiesgoTester {

public static void main(String[] args) {
	Scanner in = new Scanner(System.in);
	String valor1;
	PrimaDeRiesgo Letras;
	int numCasos;
	numCasos = in.nextInt();
	try {
		for (int i = 0; i < numCasos; i++) {
			valor1 = in.next();
			if (valor1.length() < 50) {
				Letras = new PrimaDeRiesgo();
				
				System.out.println(Letras.isPrime(Letras.calcPrimaRiesgo(valor1, valor1.length(), 0)));
			}
		}		
	} catch (Exception e) {

	}
}
}

import java.util.Scanner;
public class DivisoresFactorialTester {

public static void main(String[] args) {
	Scanner leo = new Scanner(System.in);
	int factorial, divisor, cont;

	divisor = leo.nextInt();
	factorial = leo.nextInt();

	while (divisor > -1 || factorial > -1) {
		if ((divisor == 1) || (divisor <= factorial)
				&& ((divisor >= 0) && (factorial >= 0))) {
			System.out.println("YES");
		}else{
			System.out.println("NO");
		}	
		divisor = leo.nextInt();
		factorial = leo.nextInt();
	}

}
}

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;

public class KaprekarEdgar {

public static void main(String[] args) throws IOException {

	StringBuilder asendent = new StringBuilder();
	StringBuilder desendent = new StringBuilder();
	char[] num;
	BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
	int nNombres, repeticions = 0; 
	nNombres = Integer.parseInt(in.readLine());
	String numS;
	for (int i = 0; i < nNombres; i++) {
		numS = in.readLine();
		repeticions = 0;
		while (!numS.equals("6174")) {
			
			for (int e = numS.length(); e < 4; e++) {
				numS += "0";
			}
			num = numS.toCharArray();
			Arrays.sort(num);
			desendent.setLength(0);
			asendent.setLength(0);
			for (int o = 0; o < 4; o++) {
				desendent.append(num[3 - o]);
				asendent.append(num[o]);
			}
			numS = new String(String.valueOf(Integer.parseInt(desendent.toString())
					- Integer.parseInt(asendent.toString())));
			if (numS.equals("0")) {
				repeticions = 8;
				break;
			} else {
				repeticions++;
			}
		}
		System.out.println(repeticions);
	}
	//System.out.println("Fi del programa");
}
}