Thread: Shuffling a 2D array

public class Puzzle {
    public static String[][] grid = new String[4][4];
 
    public static void setupGame(){
        int count = 1;
        for(int i=0;i<4;i++){
            for(int j=0;j<4;j++){
                grid[i][j] = Integer.toString(count++);
            }
            grid[3][3] = "?";
 
        }
    }

My array is populated by numbers from 1-15 with a "?" as the last element. I was wondering what would be the easiest way to shuffle this so that each time a button is pressed it shuffles each position?

Do you want all 16 items in the array to be shuffled as if they were in a single array, or do you want what is in row to be shuffled only within that row or column?
If all elements as in a single array, copy them to a single dim array and use the Collections shuffle method and then copy them back to the 2 dim.

shuffled as in a single array, I'm not too sure how to get the vaulues from the 2dim array to the single however?

Use a nested loop for the 2 dim and have a separate index for the one dim

Why are you using a 2 dim array? With a little arithmetic you can use a one dim array almost as easily as a 2 dim array.

I was using a 2dim as it sets up a 4x4 grid to find the values for the game

You can simulate a 2 dim array with a one dim array by using an equation to compute the index given the row and column.
Something like: ix = row*nbrcols + col (off the top of my head, I'm sure it needs some adjustment)

You could do what I'm doing in that particular case, create an arraylist, pass the 2d array into it via for loops, then use Collections.shuffle();