java - Convert a 2D array into a 1D array

Question

Here is the code I have so far:

 public static int mode(int[][] arr) {
      ArrayList<Integer> list = new ArrayList<Integer>();
      int temp = 0;
      for(int i = 0; i < arr.length; i ++) {
          for(int s = 0; s < arr.length; s ++) {
              temp = arr[i][s];

I seem to be stuck at this point on how to get [i][s] into a single dimensional array. When I do a print(temp) all the elements of my 2D array print out one a time in order but cannot figure out how to get them into the 1D array. I am a novice :(

How to convert a 2D array into a 1D array?

The current 2D array I am working with is a 3x3. I am trying to find the mathematical mode of all the integers in the 2D array if that background is of any importance.

Answer 1

You've almost got it right. Just a tiny change:

public static int mode(int[][] arr) {
    List<Integer> list = new ArrayList<Integer>();
    for (int i = 0; i < arr.length; i++) {
        // tiny change 1: proper dimensions
        for (int j = 0; j < arr[i].length; j++) { 
            // tiny change 2: actually store the values
            list.add(arr[i][j]); 
        }
    }

    // now you need to find a mode in the list.

    // tiny change 3, if you definitely need an array
    int[] vector = new int[list.size()];
    for (int i = 0; i < vector.length; i++) {
        vector[i] = list.get(i);
    }
}