"""
Given an integer array arr[] of size n, find sum of all sub-arrays of given array.

Examples :

Input   : arr[] = {1, 2, 3}
Output  : 20
Explanation : {1} + {2} + {3} + {2 + 3} +
              {1 + 2} + {1 + 2 + 3} = 20

Input  : arr[] = {1, 2, 3, 4}
Output : 50
https://www.geeksforgeeks.org/sum-of-all-subarrays/


******* See implementation in leetcode examples *******
"""
