Count pairs in an array whose product is composite number | Java Program to implement the above approach ; Function to check if a number is prime or not ; Check if N is multiple of i or not . ; If N is multiple of i . ; Function to get the count of pairs whose product is a composite number . ; Stores the count of pairs whose product is a composite number ; Generate all possible pairs ; Stores the product of element of current pair ; If prod is a composite number ; Driver Code
import java . io . * ; class GFG { static boolean isComposite ( int N ) { for ( int i = 2 ; i * i <= N ; i ++ ) { if ( N % i == 0 ) { return true ; } } return false ; } static int compositePair ( int arr [ ] , int N ) { int res = 0 ; for ( int i = 0 ; i < N ; i ++ ) { for ( int j = i + 1 ; j < N ; j ++ ) { int prod = arr [ i ] * arr [ j ] ; if ( isComposite ( prod ) ) { res ++ ; } } } return res ; } public static void main ( String [ ] args ) { int arr [ ] = { 1 , 1 , 2 , 2 , 8 } ; int N = arr . length ; System . out . println ( compositePair ( arr , N ) ) ; } }