title: Java - How to Solve this 2D Array Hour Glass?
body: <p>I am working on a problem where I've to print the largest sum among all the hourglasses in the array. You can find the details about the problem <a href="https://www.hackerrank.com/challenges/2d-array" rel="noreferrer">here-</a></p>
  
  <p><strong>What I tried:</strong></p>
  
  <pre><code>public class Solution {
      public static void main(String[] args) {
          Scanner in = new Scanner(System.in);
          int arr[][] = new int[6][6];
          for (int arr_i = 0; arr_i &lt; 6; arr_i++) {
              for (int arr_j = 0; arr_j &lt; 6; arr_j++) {
                  arr[arr_i][arr_j] = in.nextInt();
              }
          }
  
          int sum = 0;
          int tmp_sum = 0;
          for (int arr_i = 0; arr_i &lt; 4; arr_i++) {
              for (int arr_j = 0; arr_j &lt; 4; arr_j++) {
                  if (arr[arr_i][arr_j] &gt; 0) {
                      sum = sum + (arr[arr_i][arr_j]) + (arr[arr_i][arr_j + 1]) + (arr[arr_i][arr_j + 2]);
                      sum = sum + (arr[arr_i + 1][arr_j + 1]);
                      sum = sum + (arr[arr_i + 2][arr_j]) + (arr[arr_i + 2][arr_j + 1]) + (arr[arr_i + 2][arr_j + 2]);
                      if (tmp_sum &lt; sum) {
                          tmp_sum = sum;
                      }
                      sum = 0;
                  }
              }
          }
          System.out.println(tmp_sum);
      }
  }
  </code></pre>
  
  <p><strong>Input:</strong></p>
  
  <pre><code>1 1 1 0 0 0
  0 1 0 0 0 0
  1 1 1 0 0 0
  0 9 2 -4 -4 0
  0 0 0 -2 0 0
  0 0 -1 -2 -4 0
  </code></pre>
  
  <p><strong>Output:</strong></p>
  
  <pre><code>12
  </code></pre>
  
  <p><strong>Expected Output:</strong></p>
  
  <pre><code>13
  </code></pre>
  
  <p><strong>Screenshot:</strong>
  <a href="https://i.stack.imgur.com/rnrhW.png" rel="noreferrer"><img src="https://i.stack.imgur.com/rnrhW.png" alt="enter image description here"></a></p>
  
  <p>I don't know where I'm doing wrong. I cannot understand why the expected output is <code>13</code>. According to the description given in the problem it should be <code>10</code>. Is this a wrong question or my understanding about this is wrong?</p>