LeetCode: Sum Of All Odd Length Subarrays Solution

1var sumOddLengthSubarrays = function (arr) {
2  const N = arr.length
3  const sum = arr => arr.reduce((acc, el) => acc + el, 0)
4  let res = 0
5  for (let size = 1; size <= N; size += 2) {
6    for (let i = 0; i < N - size + 1; i++) {
7      res += sum(arr.slice(i, i + size))
8    }
9  }
10  return res
11}