ArrayUtils

ArrayUtils.java

public class ArrayUtils {

    public static int[][] removeRow(int[][] array, int row) {
        if (array == null || array.length == 0 || row < 0 || row >= array[0].length) {
            return array;
        }

        int[][] newArray = new int[array.length][array[0].length - 1];
        for (int i = 0; i < array.length; i++) {
            for (int j = 0, k = 0; j < array[0].length; j++) {
                if (j != row) {
                    newArray[i][k++] = array[i][j];
                }
            }
        }

        return newArray;
    }

    public static int[][] removeColumn(int[][] array, int column) {
        if (array == null || column < 0 || column >= array.length) {
            return array;
        }

        int[][] newArray = new int[array.length - 1][];
        for (int i = 0, j = 0; i < array.length; i++) {
            if (i != column) {
                newArray[j++] = array[i];
            }
        }

        return newArray;
    }

    public static int sum(int[][] array) {
        if (array == null) {
            return 0;
        }

        int totalSum = 0;
        for (int[] row : array) {
            for (int value : row) {
                totalSum += value;
            }
        }

        return totalSum;
    }

    public static int[][] multiplyMatrix(int[][] matrix1, int[][] matrix2) {
        if (matrix1 == null || matrix2 == null || matrix1[0].length != matrix2.length) {
            return null;
        }

        int rows = matrix1.length;
        int columns = matrix2[0].length;
        int[][] result = new int[rows][columns];

        for (int i = 0; i < rows; i++) {
            for (int j = 0; j < columns; j++) {
                for (int k = 0; k < matrix1[0].length; k++) {
                    result[i][j] += matrix1[i][k] * matrix2[k][j];
                }
            }
        }

        return result;
    }
}