Find the sum of non-prime elements in the given array

Given an array arr[] and the task is to print the sum of the non-prime elements from the array.

Examples:

Input: arr[] = {1, 3, 7, 4, 9, 8}
Output: 22
Non-prime elements are {1, 4, 9, 8} and 1 + 4 + 9 + 8 = 22

Input: arr[] = {11, 4, 10, 7}
Output: 14

Recommended: Please try your approach on {IDE} first, before moving on to the solution.

Approach: Initialize sum = 0 and start traversing the array element by element, if current element is not a prime then update sum = sum + arr[i]. Print the sum in the end. Primality can be optimally tested using Sieve of Eratosthenes.

Below is the implementation of the above approach:

C++

// CPP program to find sum of 
// non-primes in given array 
#include <bits/stdc++.h> 
using namespace std; 
  
// Function to return the sum of 
// non-prime elements from the array 
int nonPrimeSum(int arr[], int n) 
{ 
    // Find maximum value in the array 
    int max_val = *max_element(arr, arr + n); 
  
    // USE SIEVE TO FIND ALL PRIME NUMBERS LESS 
    // THAN OR EQUAL TO max_val 
    // Create a boolean array "prime[0..n]". A 
    // value in prime[i] will finally be false 
    // if i is Not a prime, else true. 
    vector<bool> prime(max_val + 1, true); 
  
    // Remaining part of SIEVE 
    prime[0] = false; 
    prime[1] = false; 
    for (int p = 2; p * p <= max_val; p++) { 
  
        // If prime[p] is not changed, then 
        // it is a prime 
        if (prime[p] == true) { 
  
            // Update all multiples of p 
            for (int i = p * 2; i <= max_val; i += p) 
                prime[i] = false; 
        } 
    } 
  
    // Sum all non-prime elements in arr[] 
    int sum = 0; 
    for (int i = 0; i < n; i++) 
        if (!prime[arr[i]]) 
            sum += arr[i]; 
  
    return sum; 
} 
  
// Driver code 
int main() 
{ 
  
    int arr[] = { 1, 3, 7, 4, 9, 8 }; 
    int n = sizeof(arr) / sizeof(arr[0]); 
  
    cout << nonPrimeSum(arr, n); 
  
    return 0; 
} 

Java

// Java program to find sum of 
// non-primes in given array 
import java.util.*; 
  
class GFG 
{ 
  
//returns the maximum element 
static int max_element(int arr[]) 
{ 
    int max_e = Integer.MIN_VALUE; 
    for(int i = 0; i < arr.length; i++) 
    { 
    max_e = Math.max(max_e, arr[i]);  
    } 
    return max_e; 
} 
  
// Function to return the sum of 
// non-prime elements from the array 
static int nonPrimeSum(int arr[], int n) 
{ 
    // Find maximum value in the array 
    int max_val = max_element(arr); 
  
    // USE SIEVE TO FIND ALL PRIME NUMBERS LESS 
    // THAN OR EQUAL TO max_val 
    // Create a boolean array "prime[0..n]". A 
    // value in prime[i] will finally be false 
    // if i is Not a prime, else true. 
    boolean prime[] = new boolean[max_val + 1]; 
      
    for(int i = 0; i < prime.length; i++) 
    prime[i] = true; 
  
    // Remaining part of SIEVE 
    prime[0] = false; 
    prime[1] = false; 
    for (int p = 2; p * p <= max_val; p++)  
    { 
  
        // If prime[p] is not changed, then 
        // it is a prime 
        if (prime[p] == true)  
        { 
  
            // Update all multiples of p 
            for (int i = p * 2; i <= max_val; i += p) 
                prime[i] = false; 
        } 
    } 
  
    // Sum all non-prime elements in arr[] 
    int sum = 0; 
    for (int i = 0; i < n; i++) 
        if (!prime[arr[i]]) 
            sum += arr[i]; 
  
    return sum; 
} 
  
// Driver code 
public static void main(String args[]) 
{ 
  
    int arr[] = { 1, 3, 7, 4, 9, 8 }; 
    int n = arr.length; 
    System.out.println( nonPrimeSum(arr, n)); 
} 
} 
  
// This code is contributed by Arnab Kundu 

Python3

# Python3 program to find sum of non-primes  
# in given array  
  
# from math lib. import sqrt 
from math import sqrt 
  
# Function to return the sum of  
# non-prime elements from the array  
def nonPrimeSum(arr, n) : 
      
    # Find maximum value in the array  
    max_val = max(arr) 
  
    # USE SIEVE TO FIND ALL PRIME NUMBERS   
    # LESS THAN OR EQUAL TO max_val  
    # Create a boolean array "prime[0..n]".  
    # A value in prime[i] will finally be  
    # false if i is Not a prime, else true.  
    prime = [True] * (max_val + 1)  
  
    # Remaining part of SIEVE  
    prime[0] = False
    prime[1] = False
      
    for p in range(2, int(sqrt(max_val)) + 1) : 
  
        # If prime[p] is not changed,  
        # then it is a prime  
        if (prime[p] == True) : 
  
            # Update all multiples of p  
            for i in range(p * 2, max_val + 1, p) : 
                prime[i] = False
          
    # Sum all non-prime elements in arr[]  
    sum = 0
    for i in range(0, n) :  
        if (not prime[arr[i]]) : 
            sum += arr[i] 
  
    return sum
  
# Driver code  
if __name__ == "__main__" : 
  
    arr= [ 1, 3, 7, 4, 9, 8 ]  
    n = len(arr)  
  
    print(nonPrimeSum(arr, n)) 
  
# This code is contributed by Ryuga 

C#

// C# program to find sum of non-primes  
// in given array 
using System; 
  
class GFG 
{ 
  
// returns the maximum element 
static int max_element(int[] arr) 
{ 
    int max_e = int.MinValue; 
    for(int i = 0; i < arr.Length; i++) 
    { 
        max_e = Math.Max(max_e, arr[i]);  
    } 
    return max_e; 
} 
  
// Function to return the sum of 
// non-prime elements from the array 
static int nonPrimeSum(int[] arr, int n) 
{ 
    // Find maximum value in the array 
    int max_val = max_element(arr); 
  
    // USE SIEVE TO FIND ALL PRIME NUMBERS 
    // LESS THAN OR EQUAL TO max_val 
    // Create a boolean array "prime[0..n]".  
    // A value in prime[i] will finally be  
    // false if i is Not a prime, else true. 
    bool[] prime = new bool[max_val + 1]; 
      
    for(int i = 0; i < prime.Length; i++) 
    prime[i] = true; 
  
    // Remaining part of SIEVE 
    prime[0] = false; 
    prime[1] = false; 
    for (int p = 2; p * p <= max_val; p++)  
    { 
  
        // If prime[p] is not changed,  
        // then it is a prime 
        if (prime[p] == true)  
        { 
  
            // Update all multiples of p 
            for (int i = p * 2; 
                     i <= max_val; i += p) 
                prime[i] = false; 
        } 
    } 
  
    // Sum all non-prime elements in arr[] 
    int sum = 0; 
    for (int i = 0; i < n; i++) 
        if (!prime[arr[i]]) 
            sum += arr[i]; 
  
    return sum; 
} 
  
// Driver code 
public static void Main() 
{ 
    int[] arr = { 1, 3, 7, 4, 9, 8 }; 
    int n = arr.Length; 
    Console.WriteLine(nonPrimeSum(arr, n)); 
} 
} 
  
// This code is contributed  
// by Mukul Singh. 

PHP

<?php 
// PHP program to find sum of 
// non-primes in given array 
  
// Function to return the sum of 
// non-prime elements from the array 
function nonPrimeSum($arr, $n) 
{ 
    // Find maximum value in the array 
    $max_val = max($arr); 
  
    // USE SIEVE TO FIND ALL PRIME NUMBERS LESS 
    // THAN OR EQUAL TO max_val 
    // Create a boolean array "prime[0..n]". A 
    // value in prime[i] will finally be false 
    // if i is Not a prime, else true. 
    $prime = array_fill(0, $max_val + 1, true); 
  
    // Remaining part of SIEVE 
    $prime[0] = false; 
    $prime[1] = false; 
    for ($p = 2; $p * $p <= $max_val; $p++) 
    { 
  
        // If prime[p] is not changed, then 
        // it is a prime 
        if ($prime[$p] == true)  
        { 
  
            // Update all multiples of p 
            for ($i = $p * 2;  
                 $i <= $max_val; $i += $p) 
                $prime[$i] = false; 
        } 
    } 
  
    // Sum all non-prime elements in arr[] 
    $sum = 0; 
    for ($i = 0; $i < $n; $i++) 
        if (!$prime[$arr[$i]]) 
             $sum += $arr[$i]; 
  
    return $sum; 
} 
  
// Driver code 
$arr = array( 1, 3, 7, 4, 9, 8 ); 
$n = count($arr); 
  
echo nonPrimeSum($arr, $n); 
  
// this code is contributed by mits 
?> 

Output:

My Personal Notes

Recommended: Please try your approach on {IDE} first, before moving on to the solution.

C++

Java

Python3

C#

PHP

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