How Would I Solve Sudoku Java Project? I Tips for Better Coding from the Expert

sudoku java project helpThe man has invented a lot of things that has set him aside from his contemporaries. And one of those amazing inventions is the ability to stimulate his brain in moments of leisure by actively involving thought. Folks, this is the beauty of being human; having the ability to break down a puzzle to its very last core. And to create one such as the Sudoku Java project trough Java game programming. In fact, the dopamine levels released from such an affair can be just as rewarding as the ‘extra-curricular’ activities some of us indulge in at night! Okay, not that we’re calling you out on your night crawling affairs or anything, but solving a puzzle can be a great substitute as well, don’t you think?

Now, one of the most enjoyable puzzles out there is Sudoku. Yep, we’re pretty sure you’ve seen it in today’s newspaper. Those stacks of boxes that have some numbers missing and you’ve got to fill them up? Probably your dad tries to solve it while sipping his coffee and making dad noises in the background. Or maybe your mum has a go at it after prepping your siblings for school and making sure they catch the bus. All in all, it’s a fun-filled and engaging activity!

But What Is Sudoku Really?

Now, let’s get down to the basics. Sudoku is a puzzle game of Japanese origin made for the brilliant! Okay, let’s stop having delusions of grandeur. It’s a simple game consisting of a grid of minute boxes known as cells. These cells are stacked up against each other and are nine high and wide, thus bringing the total cell count to 81! Some of these cells are usually filled up enough to live some room for your imagination and cognitive skills to kick into high gear!

Now, the objective of the game is easy. All you need to do is fill in the boxes with numbers and ensure that there are no repeated numbers in any row, column, or blocks. Once this is done, you, my friend, have mastered a Sudoku puzzle!

How Can You Implement Sudoku Java Project?

We’re going to have a look at how one can implement a Sudoku java code. Don’t worry, we’ll be taking it slow and outlining every step by step process in both coding and programming! Our java Sudoku game will also include an interface that will have the ability to access user help as well as check for any errors that will be present. In fact, the help section will be able to make all the possible fields for a given selected number. After the process of error checking, the program will further mark validated fields green and the invalidated ones red. We will use the following important rules during the implementation process: (it’s kind of like our own personal law of robotics)

  • In each and every game, there is only a singular solution
  • As a requirement of Sudoku, an integer will only appear once in the same column, row, or block (a 3*3 region)

Great! Now let’s get started on how to make a Sudoku game in Java!

One thing you have to note and of course the most important part of creating a Sudoku game java project is the game class. It should contain the following functionalities as mentioned below:
  • Ability to make a new solution.
  • Create a new game from a given solution.
  • Ability to monitor the input of the user.
  • Cross-check the user’s input with that of the generated solution.
  • Ability to monitor a selected number.
  • Ability to monitor the help function which can be on or off during a given time.
  • Generate a new solution. Before generating the game, we kick off by first generating a solution. This can be done by first calling generateSudoku (new int [9][9],0). This is done as shown below:
 private int[][] generateSolution(int[][] game, int index) {
if (index > 80)

return game;

int x = index % 9;

int y = index / 9;

List<Integer> numbers = new ArrayList<Integer>();

for (int i = 1; i <= 9; i++)

numbers.add(i);

Collections.shuffle(numbers);

while (numbers.size() > 0) {

int number = getNextPossibleNumber(game, x, y, numbers);

if (number == -1)

return null;

game[y][x] = number;

int[][] tmpGame = generateSolution(game, index + 1);

if (tmpGame != null)

return tmpGame;

game[y][x] = 0; } return null; }
  • Obtaining the next possible number – Now, the second step in the process is to obtain the next possible number using the method getNextPossibleNumber(int[][], int, int, List<Integer>)
private int getNextPossibleNumber(int[][] game, int x, int y, List<Integer> numbers){

while (numbers.size() > 0) {

int number = numbers.remove(0);

if (isPossibleX(game, y, number)

&& isPossibleY(game, x, number)

&& isPossibleBlock(game, x, y, number))

return number;

}

return -1; }

  • Generate the game – The third process is to generate the game. This can simply be done by repeatedly eliminating a random field but at the same time ensuring that the game is still valid. (by this, we mean that there is only one solution for the game. This is done by the user calling the first method, which then uses the second method. This is done with the following steps:
  • You first fill up a list of possible solutions. So don’t hesitate to get in touch with us for essential Sudoku java project help and we’ll get to you in a jiffy!
  • Shuffling of the list then takes place
  • Pass the list to generateGame(int[][], List<Integer>) and the required value will then be returned.
private int[][] generateGame(int[][] game) {

List<Integer> positions = new ArrayList<Integer>();

for (int i = 0; i < 81; i++)

positions.add(i);

Collections.shuffle(positions);

return generateGame(game, positions);

}

Considering that the list has positions, the following will take place:

  • A position is stored in the variable that will be extracted from the list.
  • The x and y will then be calculated from the said position
  • The position value is then stored in variable temp.
  • The position value is then set to 0
  • The game will then be returned.
  • Code for pass default values
private int[][] generateGame(int[][] game, List<Integer> positions) {

while (positions.size() > 0) {

int position = positions.remove(0);

int x = position % 9;

int y = position / 9;

int temp = game[y][x];

game[y][x] = 0;

if (!isValid(game))

game[y][x] = temp; } return game;

}

It’s advisable to use int[]{0} as it is the frequently used way to pass an integer by address rather than by the value.

  • Passing an integer
private boolean isValid(int[][] game) {

return isValid(game, 0, new int[] { 0 });

}

How to Check for a Valid Game

As you are aware by now, a game is valid if it only has one solution. In the event that there is more than one solution, the search will immediately be terminated and the method will automatically return a false. The following code shows how this is executed:

private boolean isValid(int[][] game, int index, int[] numberOfSolutions) {

if (index > 80)

return ++numberOfSolutions[0] == 1;

int x = index % 9;

int y = index / 9;

if (game[y][x] == 0) {

List<Integer> numbers = new ArrayList<Integer>();

for (int i = 1; i <= 9; i++)

numbers.add(i);

while (numbers.size() > 0) {

int number = getNextPossibleNumber(game, x, y, numbers);

if (number == -1)

break;

game[y][x] = number;

if (!isValid(game, index + 1, numberOfSolutions)) {

game[y][x] = 0;

return false;

}

game[y][x] = 0;

}

} else if (!isValid(game, index + 1, numberOfSolutions))

return false;

return true;

}
  • Checking the game – Now, the final piece in your Sudoku project in java is to check the game. This is done by checking out the user input. This is done by comparing the fields of the game with those of the solution. The final result is then saved in a Boolean array!
public void checkGame() {

selectedNumber = 0;

for (int y = 0; y < 9; y++) {

for (int x = 0; x < 9; x++)

check[y][x] = game[y][x] == solution[y][x];

}

setChanged();

notifyObservers(UpdateAction.CHECK); }

Voila! So there you have it. In case you’d like any further assistance with the Sudoku solver algorithm Java, don’t hesitate to contact our professional services to set you straight on the right track! Lastly, we also offer essential java game programming in a vast array of subjects for your convenience.

So don’t hesitate to get in touch with us for essential Sudoku java project help and we’ll get to you in a jiffy!