Equilibrium Index of an Array

Given an array of integers `nums`, find the equilibrium index of the array. An equilibrium index is an index such that the sum of elements at lower indices equals the sum of elements at higher indices. Return the first (0-based) equilibrium index found. If no such index exists, return `-1`. ### Constraints - `1 <= nums.length <= 10^5` - `-10^4 <= nums[i] <= 10^4` ### Input Format A single line containing space-separated integers representing `nums`. ### Output Format Print the 0-based equilibrium index, or -1.