2. 3n + 1

sources : http://www.programming-challenges.com/pg.php?page=downloadproblem&probid=110101&format=html

As I need to break my dead brain recently, I make a goal to solve the problems of Programming Challenges site. When you enter the site, you can see various types of problems we can solve by programming languages (e.g., c or java). In case of JAVA, there were lots of complaints from users, he(?) made a skeleton.

My coding is not perfect. (First time, I could not understand the problem exactly due to my poor English skills. :()

 

/*

 * Main.java

 *  java program model for www.programming-challenges.com

 */

 

import java.io.*;

import java.util.*;

 

class Main implements Runnable{

    static String ReadLn(int maxLength){  // utility function to read from stdin,

                                          // Provided by Programming-challenges, edit for style only

        byte line[] = new byte [maxLength];

        int length = 0;

        int input = -1;

        try{

            while (length < maxLength){//Read untill maxlength

                input = System.in.read();

                if ((input < 0) || (input == '\n')) break; //or untill end of line ninput

                line [length++] += input;

            }

 

            if ((input < 0) && (length == 0)) return null;  // eof

            return new String(line, 0, length);

        }catch (IOException e){

            return null;

        }

    }

 

    public static void main(String args[])  // entry point from OS

    {

        Main myWork = new Main();  // Construct the bootloader

        myWork.run();            // execute

    }

 

    public void run() {

        new myStuff().run();

    }

}

class myStuff implements Runnable{

private static int MAX_VALUE = 1000000;

 

    public void run(){

int firstInput = 0;

int secondInput = 0;

int calTimes = 0;

 

Scanner readIn = new Scanner(System.in);

 

while (readIn.hasNextLine()) {

firstInput = readIn.nextInt();

secondInput = readIn.nextInt();

if (checkCondition(firstInput) && checkCondition(secondInput)) {

calTimes = firstInput > secondInput ? calFunc (secondInput, firstInput) : calFunc (firstInput, secondInput);

System.out.printf("%d %d %d\n", firstInput, secondInput, calTimes);

} else {

System.out.printf("%d %d %d\n", firstInput, secondInput, 0);

}

}

 

readIn.close();

    }

    

private static boolean checkCondition (int input) {

if ((input > MAX_VALUE) || (input == 0))

return false;

else

return true;

}

 

private static int calFunc (int minInput, int maxInput) {

int output = 0;

int calTimes = 0;

int maxCalTimes = 0;

 

for (int ii=maxInput; ii>=minInput; ii--) {

output = ii;

while ((output > 1) && (calTimes < MAX_VALUE)) {

if ((output & 1) == 0) {

output = output / 2;

} else {

output = output * 3 + 1;

}

calTimes++;

}

 

if (calTimes > maxCalTimes)

maxCalTimes = calTimes;

 

calTimes = 0;

}

 

return maxCalTimes+1;

}

    // You can insert more classes here if you want.

}