# Absolute Difference between the Product of Non-Prime numbers and Prime numbers of an Array?

CServer Side ProgrammingProgramming

Here we will see how we can find the absolute difference between the product of all prime numbers and all non-prime numbers of an array. To solve this problem, we have to check whether a number is prime or not. One possible way for primality testing is by checking a number is not divisible by any number between 2 to square root of that number. So this process will take 𝑂(√𝑛) amount of time. Then get the product and try to find the absolute difference.

## Algorithm

#### diffPrimeNonPrimeProd(arr)

begin
prod_p := product of all prime numbers in arr
prod_np := product of all non-prime numbers in arr
return |prod_p – prod_np|
end

## Example

Live Demo

#include <iostream>
#include <cmath>
using namespace std;
bool isPrime(int n){
for(int i = 2; i<=sqrt(n); i++){
if(n % i == 0){
return false; //not prime
}
}
return true; //prime
}
int diffPrimeNonPrimeProd(int arr[], int n) {
int prod_p = 1, prod_np = 1;
for(int i = 0; i<n; i++){
if(isPrime(arr[i])){
prod_p *= arr[i];
} else {
prod_np *= arr[i];
}
}
return abs(prod_p - prod_np);
}
main() {
int arr[] = { 4, 5, 3, 8, 13, 10};
int n = sizeof(arr) / sizeof(arr[0]);
cout << "Difference: " << diffPrimeNonPrimeProd(arr, n);
}

## Output

Difference: 125
Published on 26-Jul-2019 10:19:46