Diagonal Difference

import java.io.*;
import java.math.*;
import java.security.*;
import java.text.*;
import java.util.*;
import java.util.concurrent.*;
import java.util.regex.*;

class Result {

    /*
     * Complete the 'diagonalDifference' function below.
     *
     * The function is expected to return an INTEGER.
     * The function accepts 2D_INTEGER_ARRAY arr as parameter.
     */

    public static int diagonalDifference(List<List<Integer>> arr) {
    // Write your code here
      int sum1=0;
      int sum2=0;
      int k=arr.size()-1;
      for(int i =0; i<arr.size(); i++ )
      {
          for(int j=0; j<arr.size(); j++)
          {
              if(i==j)
              sum1=sum1+arr.get(i).get(j);
            

          }
                
                 sum2=sum2+arr.get(k).get(i);
                 k--;
        
      }
      int diff=Math.abs(sum1-sum2);
      return diff;

    }

}

public class Solution {
    public static void main(String[] args) throws IOException {
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(System.getenv("OUTPUT_PATH")));

        int n = Integer.parseInt(bufferedReader.readLine().trim());

        List<List<Integer>> arr = new ArrayList<>();

        for (int i = 0; i < n; i++) {
            String[] arrRowTempItems = bufferedReader.readLine().replaceAll("\\s+$", "").split(" ");

            List<Integer> arrRowItems = new ArrayList<>();

            for (int j = 0; j < n; j++) {
                int arrItem = Integer.parseInt(arrRowTempItems[j]);
                arrRowItems.add(arrItem);
            }

            arr.add(arrRowItems);
        }

        int result = Result.diagonalDifference(arr);

        bufferedWriter.write(String.valueOf(result));
        bufferedWriter.newLine();

        bufferedReader.close();
        bufferedWriter.close();
    }
}