public class RowSort {

    public static void main (String[] argv)
    {
        // Some test data:
        int[][] A = {
            {1, 0, 1},
            {1, 1, 1},
            {1, 0, 0},
            {0, 0, 0}
        };

        // Before:
        print (A);

        rowSort (A);

        // After:
        print (A);
    }


    static void rowSort (int[][] X)
    {
        // Simple Selection Sort. We are sorting only rows.
        for (int row=0; row<X.length; row++) {

            // This is the minimum so far.
            int min = rowSum (X[row]);
            int bestRow = row;

            // Scan remainder to see if there's a better one.
            for (int row2=row+1; row2<X.length; row2++) {
                int sum = rowSum (X[row2]);
                if (sum < min) {
                    min = sum;
                    bestRow = row2;
                }
            }

            // This is a pointer swap: X[row] is NOT an int. It's a pointer to int[].
            int[] temp = X[row];
            X[row] = X[bestRow];
            X[bestRow] = temp;
        }
    }


    static int rowSum (int[] Y)
    {
        int sum = 0;
        for (int i=0; i<Y.length; i++) {
            sum += Y[i];
        }
        return sum;
    }
    

    
    static void print (int[][] X)
    {
        System.out.println ("\nArray:");
        for (int i=0; i<X.length; i++) {
            for (int j=0; j<X[i].length; j++) {
                System.out.print (" " + X[i][j]);
            }
            System.out.println ();
        }
    }
    

}