How Can I print one dimension array of integer into two dimensional array

Question

Suppose, I take a one-dimensional array of integer

A = {1,2,3,4,5,6,7,8, 9, 10, 11, 12}

Now, I want to to rearrange the integers in A in a two dimensional array with p rows and q columns in diagonal fashion. Where, p=3 and q=4.

Output will be like this:

1 2 4 7
3 5 8 10
6 9 11 12

Answer 1

You can try the following approach:

1) Initialize a 2d array of the specified dimension, i.e p by q
2) For each cell in the first row, fill its anti-diagonal ( like from north-east to south-west direction) with the next available elements in your 1d array.
3) After the first row is processed, similarly do step 2 for each remaining cell in the last column of the 2d array.

Finally, your 2d array will hold the answer you want (i.e numbers filled in an anti-diagonal fashion)

Answer 2

To have this result you could do this:

int z = 0;
for(int i = 0; i < 3; i++){
    for (int j = 0; j < 4; j++){
       System.out.print(A[z]);
       z++;
    }
   System.out.println();
}

This uses nested for loops to loop through the i and j, equivalent to the p and q rows and columns. The inner loop includes a z counter, which is the index in the original array. Be sure to include a definition of A[] in your code.

Answer 3

You can do it like this,

public class Main {

    public static void main(String[] args) {
        int[] array = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12};
        int[][] diagonalArray = createDiagonalArray(array, 3, 4);
        print2DArray(diagonalArray);
    }

    private static int[][] createDiagonalArray(int[] array, int p, int q) {

        int[][] input = new int[p][q];
        for (int j = 0; j < p; j++) {
            for (int i = 0; i < q; i++) {
                input[j][i] = array[j * q + i];
            }
        }

        final int numRows = input.length;
        final int numColumns = input[0].length;
        int[][] result = new int[numRows][numColumns];

        int rowIndex = 0;
        int columnIndex = 0;
        int currentRow = 0;
        int currentColumn = 0;
        for (int i = 0; i < numRows; i++) {
            for (int j = 0; j < numColumns; j++) {
                result[currentRow][currentColumn] = input[i][j];
                if (currentRow == numRows - 1) {
                    if (numRows < numColumns && columnIndex < numColumns - 1) {
                        currentRow = 0;
                        currentColumn = ++columnIndex;
                    } else {
                        currentRow = ++rowIndex;
                        currentColumn = numColumns - 1;
                    }
                } else if (currentColumn == 0) {
                    if (columnIndex < numColumns - 1) {
                        currentRow = rowIndex;
                        currentColumn = ++columnIndex;
                    } else {
                        currentColumn = columnIndex;
                        currentRow = ++rowIndex;
                    }
                } else {
                    currentRow++;
                    currentColumn--;
                }

            }
        }
        return result;
    }

    private static void print2DArray(int[][] diagonalArray) {
        for (int j = 0; j < 3; j++) {
            for (int i = 0; i < 4; i++) {
                System.out.print(diagonalArray[j][i] + " ");
            }
            System.out.println();
        }
    }
}

The two dimensional part was taken from here