Array of array products -

ArrayOfArrayProducts.cpp

#include <iostream>
#include <vector>

using namespace std;

vector<long> arrayOfArrayProducts(const vector<int>& arr) 
{
  // edge case, one element in the array
  
  vector<long> res = {};
  vector<long> leftProducts(arr.size());  // reduce to one variable [8, 10, 2], leftProduct[3]
  vector<long> rightProducts(arr.size());
  
  leftProducts[0] = arr[0]; // 1, 
  int length = arr.size(); 
  
  for(int i = 1; i < length; ++i) {
    leftProducts[i] = leftProducts[i - 1] * arr[i];
  }
  
  rightProducts[length-1] = arr[length - 1];
  
  for(int i = arr.size()-2; i >=0; --i) {
    rightProducts[i] = arr[i] * rightProducts[i+1];
  }
  
  for(int i = 0; i < length; ++i) {
    if(i == 0)
    {
      res.push_back(rightProducts[1]);
    }
    else if(i == length - 1)
    {
        res.push_back(leftProducts[length -2]);  // run out of index ? - 
    }
    else
    {
        res.push_back(leftProducts[i - 1] * rightProducts[i + 1]);  // 3 elements in the array      
    }    
  }
  
  // your code goes here

  return res;
}

int main() {
  vector<int> arr = {8,10,2};
  vector<long> res = arrayOfArrayProducts(arr);
  for(auto u : res)
    cout << u << ' ';
  return 0;
}

/*
[8, 10, 2]

1, 1 * 8. 8 *10 -> 2 
*/