Description
Given an array of positive integers arr, return the sum of all possible odd-length subarrays of arr. A subarray is a contiguous subsequence of the array.
Examples
Input:
arr = [1,4,2,5,3]Output:
58Explanation:
All odd-length subarrays sum.
Input:
arr = [7]Output:
7Explanation:
With only one element, there's only one subarray of odd length (length 1): [7]. The sum is 7.
Input:
arr = [2,1,3,4]Output:
24Explanation:
Odd-length subarrays: length 1: [2]=2, [1]=1, [3]=3, [4]=4; length 3: [2,1,3]=6, [1,3,4]=8. Total: 2+1+3+4+6+8=24.
Constraints
- •
1 ≤ arr.length ≤ 100