findEquilibrium second method

#include <iostream>
using namespace std;
class Solution {
    public:
    
    int findEquilibrium(vector<int> &arr){
        int n = arr.size();
        vector<int> pre(n);
        vector<int> suff(n);
        
        pre[0] = arr[0];
        // calculate prefix array
        for(int i=1;i<n;i++)
        {
            pre[i]= pre[i-1]+arr[i];
        }
        
        //calculate suffix arry
        suff[n-1] = arr[n-1];
        for(int i=n-2;i>=0;i--)
        {
            suff[i] = suff[n-2]+arr[i];
        }
        
        for(int i=0;i<n;i++)
        {
            if(pre[i]==suff[i]){
                return i;
            }
        }
        return -1;
    }
}
int main() {
    cout << "Function to fine equilibrium point in array!";
    
    return 0;
}