We Keep Coding

Algorithm to find `balanced number` - the same number of even and odd dividers

We define balanced number as number which has the same number of even and odd dividers e.g (2 and 6 are balanced numbers). I tried to do task for polish SPOJ however I always exceed time.
The task is to find the smallest balance number bigger than given on input.
There is example input:
2 (amount of data set)
1
2
and output should be:
2
6
This is my code:
import java.math.BigDecimal;
import java.util.Scanner;
public class Main {
private static final BigDecimal TWO = new BigDecimal("2");
public static void main(String[] args) throws java.lang.Exception {
Scanner in = new Scanner(System.in);
int numberOfAttempts = in.nextInt();
for (int i = 0; i < numberOfAttempts; i++) {
BigDecimal fromNumber = in.nextBigDecimal();
findBalancedNumber(fromNumber);
}
}
private static boolean isEven(BigDecimal number){
if(number.remainder(new BigDecimal("2")).compareTo(BigDecimal.ZERO) != 0){
return false;
}
return true;
}
private static void findBalancedNumber(BigDecimal fromNumber) {
BigDecimal potentialBalancedNumber = fromNumber.add(BigDecimal.ONE);
while (true) {
int evenDivider = 0;
int oddDivider = 1; //to not start from 1 as divisor, it's always odd and divide potentialBalancedNumber so can start checking divisors from 2
if (isEven(potentialBalancedNumber)) {
evenDivider = 1;
} else {
oddDivider++;
}
for (BigDecimal divider = TWO; (divider.compareTo(potentialBalancedNumber.divide(TWO)) == -1 || divider.compareTo(potentialBalancedNumber.divide(TWO)) == 0); divider = divider.add(BigDecimal.ONE)) {
boolean isDivisor = potentialBalancedNumber.remainder(divider).compareTo(BigDecimal.ZERO) == 0;
if(isDivisor){
boolean isEven = divider.remainder(new BigDecimal("2")).compareTo(BigDecimal.ZERO) == 0;
boolean isOdd = divider.remainder(new BigDecimal("2")).compareTo(BigDecimal.ZERO) != 0;
if (isDivisor && isEven) {
evenDivider++;
} else if (isDivisor && isOdd) {
oddDivider++;
}
}
}
if (oddDivider == evenDivider) { //found balanced number
System.out.println(potentialBalancedNumber);
break;
}
potentialBalancedNumber = potentialBalancedNumber.add(BigDecimal.ONE);
}
}
}
It seems to work fine but is too slow. Can you please help to find way to optimize it, am I missing something?

As #MarkDickinson suggested, answer is:
private static void findBalancedNumberOptimized(BigDecimal fromNumber) { //2,6,10,14,18,22,26...
if(fromNumber.compareTo(BigDecimal.ONE) == 0){
System.out.println(2);
}
else {
BigDecimal result = fromNumber.divide(new BigDecimal("4")).setScale(0, RoundingMode.HALF_UP).add(BigDecimal.ONE);
result = (TWO.multiply(result).subtract(BigDecimal.ONE)).multiply(TWO); //2(2n-1)
System.out.println(result);
}
}
and it's finally green, thanks Mark!

For Loop to score bowling

I'm working on a project for a potential internship to take a String input of bowling scores and add them up to a final score. I'm having difficult passing one of my tests and was wondering if you could help me figure out my fault.
The test that is not working is isNinetySix and it is giving me a result of 98 instead. Please help!
public class Game {
private int roll = 0;
private int[] rolls = new int[21];
public void rolls(String scoreCard) {
for (int i=0; i< scoreCard.length(); i++) {
if (scoreCard.charAt(i) == 'X') {
rolls[roll++] = 10;
} else if (scoreCard.charAt(i) == '/') {
rolls[roll++] = 10;
} else if (scoreCard.charAt(i) == '-') {
} else {
int x = scoreCard.charAt(i);
rolls[roll++] = x - '0';
}
}
}
public int score() {
int score = 0;
int cursor = 0;
for (int frame = 0; frame < 10; frame++) {
if (isStrike(cursor)) {
score += 10 + rolls[cursor+1] + rolls[cursor+2];
cursor ++;
} else if (isSpare(cursor)) {
score += 10 + rolls[cursor+2];
cursor += 2;
} else {
score += rolls[cursor] + rolls[cursor+1];
cursor += 2;
}
}
return score;
}
private boolean isStrike(int cursor) {
return rolls[cursor] == 10;
}
private boolean isSpare(int cursor) {
return rolls[cursor] + rolls[cursor+1] == 10;
}
//Print scores for each frame
public void printFrameScore(int[] frame) {
for (int i = 1; i < frame.length; i++) {
System.out.println(i + ": " + frame[i]);
}
}
public void displayRolls() {
for (int i = 0; i < rolls.length; i++) {
System.out.print(rolls[i] + ", ");
}
}
}
Tests
import static org.junit.Assert.*;
import static org.hamcrest.CoreMatchers.is;
import org.junit.Before;
import org.junit.Test;
public class GameTest {
private Game game;
#Before
public void setUp(){
game = new Game();
}
#Test
public void isPerfect() {
game.rolls("X-X-X-X-X-X-X-X-X-X-XX");
assertThat(game.score(), is(300));
}
#Test
public void isGutter() {
game.rolls("00-00-00-00-00-00-00-00-00-00");
assertThat(game.score(), is(0));
}
#Test
public void isNinety() {
game.rolls("45-54-36-27-09-63-81-18-90-72");
assertThat(game.score(), is(90));
}
#Test
public void isOneFifty(){
game.rolls("5/-5/-5/-5/-5/-5/-5/-5/-5/-5/-5");
assertThat(game.score(), is(150));
}
#Test
public void isNinetySix() {
game.rolls("45-54-36-27-09-63-81-18-90-7/-5");
assertThat(game.score(), is(96));
}
}

The problem here seems to be that your isSpare() function never returns true because you assigned each / a value of 10. The result of the addition of the two rolls in a frame with a spare was more than 10. If I were you I would try to clean up the assignment of / to actually be 10 - prev_role_score. This would be cleaner than making isSpare() check for greater than 10. There are other ways to clean up the code to, you could try to refactor some to impress whoever you submit to.
} else if (scoreCard.charAt(i) == '/') {
int diff = 10 - rolls[roll - 1];
rolls[roll++] = diff;
}

Your code is failing in the below block (after your 9th frame, you're at a score of 81). You're code is looking at the index that contains the value 7 and the / which you represent as 10, thereby giving you 17 rather than 10 for the spare.
...
} else {
score += rolls[cursor] + rolls[cursor+1];
cursor += 2;
}
...
So, if I were making suggestions, and I'm not sure what the expectations are for your project, I would tell you to think about easier ways to traverse your string by splitting, searching, then adding. Below is a quick example:
public void rolls(String scorecard) {
String [] framesets = scorecard.split("-");
//hunt for special cases like spare and strikes
//do work to hold your scores
}

(Arraylist) Crashes when user defined String input

The purpose of the program is to let the user input 5 numbers and select which game they would like to compare them to (lotto/lottoplus1/lottoplus2) with each having a unique set of 5 numbers, then to be stored in an arraylist.
The national lottery run three draws on each night: Lotto, Lotto plus one and Lotto plus 2.
generate numbers for each of these draws.
When a user enters a line of numbers they should also enter either:"lotto", "plus1", or "plus2" to specify which of the draws their numbers should be compared to.
This value should then be assigned to that specific line of numbers and the numbers on that line should be compared against each set of Lotto numbers as required.
Heres my problem! When I input my five numbers then lets say 'plus1' to assign the comparison of those numbers to lotteryPlusOne it crashes and outputs this message:
Exception in thread "main" java.lang.NullPointerException at lottoapp.lottoCounter.compareNums(lottoCounter.java:136) at lottoapp.LottoApp.main(LottoApp.java:61) C:\Users\x15587907\AppData\Local\NetBeans\Cache\8.1\executor‌​-snippets\run.xml:53‌​: Java returned: 1 BUILD FAILED (total time: 15 seconds)
Below is line 136 it is in the Instantiable class in the public void compareNums() method
l = madeUpArrayList.get(i); <-----
Main App
package lottoapp;
import javax.swing.JOptionPane;
import java.util.ArrayList;
import java.util.Arrays;
public class LottoApp {
public static void main(String[] args) {
//declare vars/objects/arrays
int[] lottery = new int[5]; //5 Winning numbers
int[] lotteryPlus1 = new int[5]; //5 Winning LP1 numbers
int[] lotteryPlus2 = new int[5]; //5 Winning LP2 numbers
String gameType;
int number1;
int number2;
int number3;
int number4;
int number5;
//array list called madeUpArrayList
ArrayList<lottoCounter> madeUpArrayList = new ArrayList();
//object declare and create
lottoCounter myCount = new lottoCounter();
//winNums/getLottery need to be initialised at top of program
myCount.winNums();
lottery = myCount.getLottery();
lotteryPlus1 = myCount.getLotteryPlus1();
lotteryPlus2 = myCount.getLotteryPlus2();
//Displays winning numbers (Testing Purposes)
System.out.println(Arrays.toString(lottery));
System.out.println(Arrays.toString(lotteryPlus1));
System.out.println(Arrays.toString(lotteryPlus2));
//Array List
for (int i = 0; i < 1; i++) {
lottoCounter l = new lottoCounter();
number1 = Integer.parseInt(JOptionPane.showInputDialog(null, "Enter number 1 "));
number2 = Integer.parseInt(JOptionPane.showInputDialog(null, "Enter number 2 "));
number3 = Integer.parseInt(JOptionPane.showInputDialog(null, "Enter number 3 "));
number4 = Integer.parseInt(JOptionPane.showInputDialog(null, "Enter number 4 "));
number5 = Integer.parseInt(JOptionPane.showInputDialog(null, "Enter number 5 "));
gameType = JOptionPane.showInputDialog(null, "Select a game type for comparison ... lotto/plus1/plus2");
l.setNumber1(number1);
l.setNumber2(number2);
l.setNumber3(number3);
l.setNumber4(number4);
l.setNumber5(number5);
l.setGameType(gameType);
madeUpArrayList.add(l);
}
//Comparison
myCount.compareNums();
//Output Lotto,Lotto Plus One and Lotto plus Two correct guesses
JOptionPane.showMessageDialog(null, "Guesses correct for Regular Lottery correct is " + myCount.getCorrectLotto());
JOptionPane.showMessageDialog(null, "Guesses correct for Lottery Plus One is " + myCount.getCorrectPlusOne());
JOptionPane.showMessageDialog(null, "Guesses correct for Lottery Plus Two is " + myCount.getCorrectPlusTwo());
}
}
Instantiable Class
package lottoapp;
import java.util.ArrayList;
public class lottoCounter {
//Variables/Constants/data members
private int correctLotto;
private int correctPlusOne;
private int correctPlusTwo;
private int[] lottery = new int[5];
private int[] lotteryPlus1 = new int[5];
private int[] lotteryPlus2 = new int[5];
private int number1;
private int number2;
private int number3;
private int number4;
private int number5;
private String gameType;
private ArrayList<lottoCounter> madeUpArrayList;
//Constructor
lottoCounter() {
correctLotto = 0;
correctPlusOne = 0;
correctPlusTwo = 0;
number1 = 0;
number2 = 0;
number3 = 0;
number4 = 0;
number5 = 0;
gameType = " ";
}
//setters
public void setCorrectLotto(int correctLotto) {
this.correctLotto = correctLotto;
}
public void setCorrectPlusOne(int correctPlusOne) {
this.correctPlusOne = correctPlusOne;
}
public void setCorrectPlusTwo(int correctPlusTwo) {
this.correctPlusTwo = correctPlusTwo;
}
public void setLottery(int[] lottery) {
this.lottery = lottery;
}
public void setLotteryPlus1(int[] lotteryPlus1) {
this.lotteryPlus1 = lotteryPlus1;
}
public void setLotteryPlus2(int[] lotteryPlus2) {
this.lotteryPlus1 = lotteryPlus2;
}
public void setNumber1(int number1) {
this.number1 = number1;
}
public void setNumber2(int number2) {
this.number2 = number2;
}
public void setNumber3(int number3) {
this.number3 = number3;
}
public void setNumber4(int number4) {
this.number4 = number4;
}
public void setNumber5(int number5) {
this.number5 = number5;
}
public void setGameType(String gameType) {
this.gameType = gameType;
}
public lottoCounter(ArrayList<lottoCounter> madeUpArrayList) {
this.madeUpArrayList = madeUpArrayList;
}
//COMPUTE
//Lottery Generator | random num generator (1-40)Lottery
public void winNums() {
for (int i = 0; i < lottery.length; i++) {//Generating 1 to 40 numbers
lottery[i] = (int) Math.floor(1 + Math.random() * 40);//Using Math.random
for (int j = 0; j < i; j++) {
if (lottery[i] == lottery[j]) {
i--;
}
}
}
//Lottery plus 1 generator
for (int i = 0; i < lotteryPlus1.length; i++) {//Generating 1 to 40 numbers
lotteryPlus1[i] = (int) Math.floor(1 + Math.random() * 40);//Using Math.random
for (int j = 0; j < i; j++) {
if (lotteryPlus1[i] == lotteryPlus1[j]) {
i--;
}
}
}
//Lottery plus 2 generator
for (int i = 0; i < lotteryPlus2.length; i++) {//Generating 1 to 40 numbers
lotteryPlus2[i] = (int) Math.floor(1 + Math.random() * 40);//Using Math.random
for (int j = 0; j < i; j++) {
if (lotteryPlus2[i] == lotteryPlus2[j]) {
i--;
}
}
}
}
//Counter for Lottery/LotteryPlusOne/LotteryPlusTwo (COMPARISON)
public void compareNums() {
for (int i = 0; i < 1; i++) {
for (int j = 0; j < 5; j++) {
lottoCounter l;
l = madeUpArrayList.get(i);
if (l.getGameType().equals("lotto")) {
if (lottery[j] == l.getNumber1() || lottery[j] == l.getNumber2() || lottery[j] == l.getNumber3() || lottery[j] == l.getNumber4() || lottery[j] == l.getNumber5()) {
correctLotto++;
}
}
if (l.getGameType().equals("plus1")) {
if (lotteryPlus1[j] == l.getNumber1() || lotteryPlus1[j] == l.getNumber2() || lotteryPlus1[j] == l.getNumber3() || lotteryPlus1[j] == l.getNumber4() || lotteryPlus1[j] == l.getNumber5()) {
correctPlusOne++;
}
}
if (l.getGameType().equals("plus2")) {
if (lotteryPlus2[j] == l.getNumber1() || lotteryPlus2[j] == l.getNumber2() || lotteryPlus2[j] == l.getNumber3() || lotteryPlus2[j] == l.getNumber4() || lotteryPlus2[j] == l.getNumber5()) {
correctPlusTwo++;
}
}
}
}
}
//getters (return values to App Class)
public int getCorrectLotto() {
return correctLotto;
}
public int getCorrectPlusOne() {
return correctPlusOne;
}
public int getCorrectPlusTwo() {
return correctPlusTwo;
}
public int[] getLottery() {
return lottery;
}
public int[] getLotteryPlus1() {
return lotteryPlus1;
}
public int[] getLotteryPlus2() {
return lotteryPlus2;
}
public int getNumber1() {
return number1;
}
public int getNumber2() {
return number2;
}
public int getNumber3() {
return number3;
}
public int getNumber4() {
return number4;
}
public int getNumber5() {
return number5;
}
public String getGameType() {
return gameType;
}
public ArrayList<lottoCounter> getMadeUpArrayList() {
return madeUpArrayList;
}
}

I am not sure about anyone else but it would be nice to have more info, like the data in the arrays: lottery, lotteryPlus1 and madeUpArrayList ect. Just to make sure that they actually have any data in them because according to your Exception you have a java.lang.NullPointerException in your method compareNums in line 136 of your class. Because you did not post line numbers I am not sure when the exception occurs.
I am assuming one of your arrays does not have any data in it or one or more of your arrays do not have 5 total entries of data in it because your for loop iterates 5 times. But again without seeing how or when your arrays are instantiated I do not think it is possible for anyone to confirm that is the cause of your problems. For example lotteryPlus2[] may only have data for lotteryPlus2[0],lotteryPlus2[1],and lotteryPlus2[2] so when j gets to 3 in the loop lotteryPlus2[3] does not exist and throws a java.lang.NullPointerException.
Also I am curious on why you use this for loop for (int i = 0; i < 1; i++){}
This loop only loops once no matter what so why have it there at all since your main method will always run at least once anyways? Honest question, I am a beginner programmer so you may be using it for something that I have no knowledge about.

Java MultiThreading Primes

been working on this program for a while and I think I've made much more progress. My java skills are not very good, but I think I'm close. Everything should compile without issue except for my "public void run" in my worker class. The program prompts the user for how many threads they want and then parses through a text file of random numbers to find all the prime numbers. My issue seems to be in the algorithm for the prime numbers. How do I write the algorithm so it parses the data down and finds the prime numbers?
I have posted the entire program below, but please see the worker class towards the bottom. Any help would be greatly appreciated in solving this issue. Thank you.
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.Scanner;
public class PrimeNumbers{
public static void main(String[] args) throws IOException {
int[] numbers = new int[100000];
int count;
int index = 0;
String datafile = "dataset529.txt"; //string which contains datafile
String line; //current line of text file
try (BufferedReader br = new BufferedReader(new FileReader(datafile))) { //reads in the datafile
while ((line = br.readLine()) != null) { //reads through each line
numbers[index++] = Integer.parseInt(line); //pulls out the number of each line and puts it in numberset[]
}
}
System.out.println("How many threads would you like to use?");
Scanner scan = new Scanner(System.in);
int z = scan.nextInt();
Thread[] threads = new Thread[z]; //creates threads as per user
worker[] finder = new worker[z]; //assigns finder to each thread created
int range = numbers.length / z; //breaks up each worker into a section depending on thread count.
for (count = 0; count < z; count++) {
int startAt = count * range;
int endAt = startAt + range;
finder[count] = new worker(startAt, endAt, numbers);
}
for (count = 0; count < z; count++) { //moves to next thread
threads[count] = new Thread(finder[count]);
threads[count].start();
}
boolean processing = false;
do {
processing = false;
for (Thread t : threads) {
if (t.isAlive()) {
processing = true;
break;
}
}
} while (processing);
for (worker worker : finder) {
System.out.println("Max of thread is: " + worker.getPrime());
}
}
public static class worker implements Runnable {
private int start;
private int stop;
private int numberset[];
public worker(int start, int stop, int[] numberset) {
this.start = start;
this.stop = stop;
this.numberset = numberset;
}
#Override
public void run() {
for (int x = start; x < stop; x++) {
if (numberset[]%3 && != 1 && != 2 && !=3)
return prime
}
}
public int getPrime() {
return true
}
}
}

nothing will output

no matter where I place the output statement, whether is it for 1 place of the array, all of the array, or even the count variable. I can't print out ANYTHING to the console. I have tried printing in the main, and in the functions. any ideas?
Edit1: I have discovered I can print inside a jswing window, but still no luck to the console, which is making error checking difficult.
Given the fact that I can still output correctly in a window, and people claim eclipse will print it out, I have deemed that the console for my ancient text editor is just incompetent, I appreciate the help
'
//=========================//
//colby moniz project 9-1 //
//Number sorter //
//=========================//
//===========================================//
//This program takes 10 integers and sorts //
//them into even, odd, and negative. //
//===========================================//
//=============//
//Import Files //
//=============//
import javax.swing.*; // DRAW DIALOG BOX CLASS
import java.awt.*; // IMPORT AWT TO CHANGE FONT AND COLORS
public class p91 {
public static void main(String[] args) {
//=================================//
//varbiles section //
//=================================//
sorter sort = new sorter(); //Creatests an instances of sorter, inside main.
int[] test = new int[10];
int inputNum;
//================================//
//Introduction windows //
//================================//
info( "This program will sort 10 intergers, \n into the catagories minimum, maximum and negitive",
"Introduction" );
//===========================//
//fill up array //
//===========================//
for(int count = 0; count < 10; count++)
{
inputNum = input("please input number " + (count + 1), "Input");
test[count] = inputNum;
}
for(int count = 0; count < 10; count++)
{
System.out.print(test[count]);
}
}
//====================================================//
//Functions //
//====================================================//
public static void info(String a, String b)
{
//================================//
//Introduction window //
//================================//
int close = JOptionPane.showConfirmDialog(null,
a, b,
JOptionPane.DEFAULT_OPTION,
JOptionPane.INFORMATION_MESSAGE);
checkCloseInt(close);
}
public static void checkCloseInt(int close)
{
//=====================================
//checks to see if user closed program
//=====================================
if ((close == JOptionPane.CLOSED_OPTION) ||
(close == JOptionPane.NO_OPTION) ||
(close == JOptionPane.CANCEL_OPTION))
System.exit(0);
}
public static int input(String a, String b)
{
//================================//
//input //
//================================//
boolean parsable;
int inputParse = 999;
String input;
do
{
input = JOptionPane.showInputDialog(null,
a, b,
JOptionPane.QUESTION_MESSAGE);
//======================//
//Check if close //
//======================//
if(input == null)
{
System.exit(0);
}
parsable = error(input);
}
while(parsable == false);
inputParse = Integer.parseInt(input);
System.out.print(inputParse);
return inputParse;
}
public static boolean error(String input)
{
//======================
//Check if parsable
//=======================
boolean parsable = true;
try
{
int inputParse = Integer.parseInt(input);
}
catch(NumberFormatException e)
{
parsable = false;
}
if(parsable == false)
{
errorWindow("Please input a number");
}
return parsable;
}
public static void errorWindow(String a)
{
//================================//
//Introduction window //
//================================//
int close = JOptionPane.showConfirmDialog(null,
a, "Error",
JOptionPane.DEFAULT_OPTION,
JOptionPane.ERROR_MESSAGE);
checkCloseInt(close);
}
}
'

Use System.out.println(); this works for me´.