Equilibrium Index in an Array

Given an array (A) of integers, find an index (i) such that the sum of the elements on the left of (i) is equal to the sum of the elements on the right of (i). Formally, find the smallest index (i) that satisfies [ \sum_{j=0}^{i-1} A[j] = \sum_{j=i+1}^{n-1} A[j] ] If no such index exists, output (-1). The input is provided as the number of elements followed by the list of integers.

inputFormat

The first line contains an integer (n) ((1 \leq n \leq 10^5)), representing the number of elements in the array. The second line contains (n) space-separated integers that constitute the array.

outputFormat

Output a single integer representing the equilibrium index. If the equilibrium index does not exist, output (-1).## sample

7
-7 1 5 2 -4 3 0

3