Rotating multi-dimensional array by 90 degrees clockwise

Question

I've been able to work out the bulk of the problem. But my output keeps throwing an exception. I'm sure it's something minor, but I can't seem to figure out how to make this work right. I'm including the exception, the task as originally worded to me, along with my code so far:

Using formula array[j][n - 1 - i] I get the following exception:

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: Index -1 out of bounds for length 4 at com.company.Main.main(Main.java:20)

If I use array[j][n - i] I get no exception, but it isn't the correct output order.

Been stuck on this for a week!

Given a rectangle array n×m in size. Rotate it by 90 degrees clockwise, by recording the result into the new array m×n in size.

Input data format:

Input the two numbers n and m, not exceeding 100, and then an array n×m in size.

Output data format:

Output the resulting array. Separate numbers by a single space in the output.

Sample Input 1:

3 4

11 12 13 14
21 22 23 24
31 32 33 34

Sample Output 1:

31 21 11
32 22 12
33 23 13
34 24 14

class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        int m = scanner.nextInt();
        int[][] array = new int[n][m];

        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                array[i][j] = scanner.nextInt();
            }
        }
        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                System.out.print(array[j][n - 1 - i] + " ");
            }
            System.out.println("");
        }
    }
}

Answer 1

If you're only rotating it 90 degrees, you're just starting from the end of the row to the beginning while moving columns left and right. So your code should just be:

int n = 3;
int m = 4;

int[][] array = {
        {11, 12, 13, 14},
        {21, 22, 23, 24},
        {31, 32, 33, 34}};

for (int col = 0; col < m; col++) {
    for (int row = n - 1; row >= 0; row--) {
        System.out.print(array[row][col] + " ");
    }
    System.out.println("");
}