Given an array of positive integers `arr`

, calculate the sum of all possible odd-length subarrays.

A subarray is a contiguous subsequence of the array.

Return *the sum of all odd-length subarrays of *`arr`

.

**Example 1:**

Input:arr = [1,4,2,5,3]Output:58Explanation:The odd-length subarrays of arr and their sums are: [1] = 1 [4] = 4 [2] = 2 [5] = 5 [3] = 3 [1,4,2] = 7 [4,2,5] = 11 [2,5,3] = 10 [1,4,2,5,3] = 15 If we add all these together we get 1 + 4 + 2 + 5 + 3 + 7 + 11 + 10 + 15 = 58

**Example 2:**

Input:arr = [1,2]Output:3Explanation:There are only 2 subarrays of odd length, [1] and [2]. Their sum is 3.

**Example 3:**

Input:arr = [10,11,12]Output:66

**Constraints:**

`1 <= arr.length <= 100`

`1 <= arr[i] <= 1000`

class Solution {
public int sumOddLengthSubarrays(int[] arr) {
}
}