Zig Zag

package com.company;

import java.util.Scanner;

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

        int rows = Integer.parseInt(scanner.nextLine());
        int cols = Integer.parseInt(scanner.nextLine());
        long sum = 0;

        for (int i = 0; i < rows; i++) {
            String line = scanner.nextLine();
            String[] arrayFromLine = line.split(" ");
            long[] numbers = new long[cols];
            for (int j = 0; j < cols; j++) {
                numbers[j] = Long.parseLong(arrayFromLine[j]);
            }
            if (i == 0) {
                for (int j = 0; j < numbers.length; j+=2) {
                    sum += numbers[j];
                }
            } else if (i == (rows - 1)) {
                if (i % 2 == 0) {
                    for (int j = 0; j < numbers.length; j+=2) {
                        sum += numbers[j];
                    }
                } else {
                    for (int j = 1; j < numbers.length; j+=2) {
                        sum += numbers[j];
                    }
                }
            } else {
                if (i % 2 == 0) {
                    for (int j = 2; j < numbers.length - 1; j+=2) {
                        sum += (numbers[j] * 2);
                    }
                    sum += numbers[0];
                } else {
                    for (int j = 1; j < numbers.length - 1; j+=2) {
                        sum += (numbers[j] * 2);
                    }
                    sum += numbers[numbers.length - 1];
                }
            }
        }
        System.out.println(sum);
    }
}