Check whether the sum of prime elements of the array is prime or not
Given an array having N elements. The task is to check if the sum of prime elements of the array is prime or not.
Examples:
Input: arr[] = {1, 2, 3} Output: Yes As there are two primes in the array i.e. 2 and 3. So, the sum of prime is 2 + 3 = 5 and 5 is also prime. Input: arr[] = {2, 3, 2, 2} Output: No
Approach: First find prime number up to 10^5 using Sieve. Then iterate over all elements of the array. If the number is prime then add it to sum. And finally, check whether the sum is prime or not. If prime then prints Yes otherwise No.
Below is the implementation of the above approach:
C++
// C++ implementation of the above approach #include <bits/stdc++.h> #define ll long long int #define MAX 100000 using namespace std; bool prime[MAX]; // Sieve to find prime void sieve() { memset (prime, true , sizeof (prime)); prime[0] = prime[1] = false ; for ( int i = 2; i < MAX; i++) if (prime[i]) for ( int j = 2 * i; j < MAX; j += i) prime[j] = false ; } // Function to check if the sum of // prime is prime or not bool checkArray( int arr[], int n) { // find sum of all prime number ll sum = 0; for ( int i = 0; i < n; i++) if (prime[arr[i]]) sum += arr[i]; // if sum is prime // then return yes if (prime[sum]) return true ; return false ; } // Driver code int main() { // array of elements int arr[] = { 1, 2, 3 }; int n = sizeof (arr) / sizeof (arr[0]); sieve(); if (checkArray(arr, n)) cout << "Yes" ; else cout << "No" ; return 0; } |
Java
// Java implementation of the above approach import java.io.*; class GFG { static int MAX = 100000 ; static boolean prime[] = new boolean [MAX]; // Sieve to find prime static void sieve() { for ( int i= 0 ;i<MAX;i++) { prime[i] = true ; } prime[ 0 ] = prime[ 1 ] = false ; for ( int i = 2 ; i < MAX; i++) if (prime[i]) for ( int j = 2 * i; j < MAX; j += i) prime[j] = false ; } // Function to check if the sum of // prime is prime or not static boolean checkArray( int arr[], int n) { // find sum of all prime number int sum = 0 ; for ( int i = 0 ; i < n; i++) if (prime[arr[i]]) sum += arr[i]; // if sum is prime // then return yes if (prime[sum]) return true ; return false ; } // Driver code public static void main (String[] args) { // array of elements int arr[] = { 1 , 2 , 3 }; int n = arr.length; sieve(); if (checkArray(arr, n)) System.out.println( "Yes" ); else System.out.println( "No" ); } } // This code is contributed by shs.. |
Python3
# Python3 implementation of above approach from math import gcd, sqrt MAX = 100000 prime = [ True ] * MAX # Sieve to find prime def sieve() : # 0 and 1 are not prime numbers prime[ 0 ] = False prime[ 1 ] = False for i in range ( 2 , MAX ) : if prime[i] : for j in range ( 2 * * i, MAX , i) : prime[j] = False # Function to check if the sum of # prime is prime or not def checkArray(arr, n) : # find sum of all prime number sum = 0 for i in range (n) : if prime[arr[i]] : sum + = arr[i] # if sum is prime # then return yes if prime[ sum ] : return True return False # Driver code if __name__ = = "__main__" : # list of elements arr = [ 1 , 2 , 3 ] n = len (arr) sieve() if checkArray(arr, n) : print ( "Yes" ) else : print ( "No" ) # This code is contributed by ANKITRAI1 |
C#
// C# implementation of the above approach using System; class GFG { static int MAX = 100000; static bool [] prime = new bool [MAX]; // Sieve to find prime static void sieve() { for ( int i = 0; i < MAX; i++) { prime[i] = true ; } prime[0] = prime[1] = false ; for ( int i = 2; i < MAX; i++) if (prime[i]) for ( int j = 2 * i; j < MAX; j += i) prime[j] = false ; } // Function to check if the sum of // prime is prime or not static bool checkArray( int [] arr, int n) { // find sum of all prime number int sum = 0; for ( int i = 0; i < n; i++) if (prime[arr[i]]) sum += arr[i]; // if sum is prime // then return yes if (prime[sum]) return true ; return false ; } // Driver code public static void Main () { // array of elements int [] arr = new int [] { 1, 2, 3 }; int n = arr.Length; sieve(); if (checkArray(arr, n)) Console.WriteLine( "Yes" ); else Console.WriteLine( "No" ); } } // This code is contributed by mits |
PHP
<?php // PHP implementation of the // above approach // Sieve to find prime function sieve() { $MAX = 100000; $prime = array ( $MAX ); for ( $i = 0; $i < $MAX ; $i ++) { $prime [ $i ] = true; } $prime [0] = $prime [1] = false; for ( $i = 2; $i < $MAX ; $i ++) if ( $prime [ $i ]) for ( $j = 2 * $i ; $j < $MAX ; $j += $i ) $prime [ $j ] = false; } // Function to check if the sum of // prime is prime or not function checkArray( $arr , $n ) { $prime = array (100000); // find sum of all prime number $sum = 0; for ( $i = 0; $i < $n ; $i ++) if ( $prime [ $arr [ $i ]]) $sum += $arr [ $i ]; // if sum is prime // then return yes if ( $prime [ $sum ]) return true; return false; } // Driver code $arr = array (1, 2, 3); $n = sizeof( $arr ); sieve(); if (checkArray( $arr , $n )) echo "Yes" ; else echo "No" ; // This code is contributed // by Akanksha Rai ?> |
Javascript
<script> // JavaScript implementation of the // above approach // function check whether a number // is prime or not function isPrime(n) { // Corner case if (n <= 1) return 0; // Check from 2 to n-1 for (let i = 2; i < n; i++) if (n % i == 0) return 0; return 1; } var prime = new Array(5); // Sieve to find prime function sieve() { for (i = 0; i <=5; i++) { prime[i] = isPrime(i); } } // Function to check if the sum of // prime is prime or not function checkArray(arr, n) { // find sum of all prime number sum = 0; for (i = 0; i <= n; i++) if (prime[arr[i]]) sum += arr[i]; // if sum is prime // then return yes if (sum) return 1; return 0; } var arr= [1, 2, 3]; n = 3; sieve(); if (checkArray(arr, n)) document.write( "Yes" ); else document.write( "No" ); </script> |
Output:
Yes
Time Complexity: O(n * log(log n))
Auxiliary Space: O(MAX)