Sum of All Odd Length Subarrays

Easy

Given an array of positive integers arr, return the sum of all elements over all contiguous subarrays of odd length.

Example 1

Input:  arr = [1,4,2,5,3]
Output: 58

Example 2

Input:  arr = [1,2]
Output: 3

Constraints

• 1 <= arr.length <= 100
• 1 <= arr[i] <= 1000