Hackerrank: 2D Array - DS Solution

1function hourglassSum(arr) {
2  const N = arr.length
3  const M = arr[0].length
4  let max = -Infinity
5
6  for (let i = 0; i < N - 2; i++) {
7    for (let j = 0; j < M - 2; j++) {
8      max = Math.max(
9        max,
10        arr[i][j] +
11          arr[i][j + 1] +
12          arr[i][j + 2] +
13          arr[i + 1][j + 1] +
14          arr[i + 2][j] +
15          arr[i + 2][j + 1] +
16          arr[i + 2][j + 2]
17      )
18    }
19  }
20
21  return max
22}