Numbers less than N which are product of exactly two distinct prime numbers | Java program to find numbers that are product of exactly two distinct prime numbers ; Function to check whether a number is a PerfectSquare or not ; Function to check if a number is a product of exactly two distinct primes ; Function to find numbers that are product of exactly two distinct prime numbers . ; Vector to store such numbers ; insert in the vector ; Print all numbers till n from the vector ; Driver function
import java . util . * ; class GFG { static boolean isPerfectSquare ( double x ) { double sr = Math . sqrt ( x ) ; return ( ( sr - Math . floor ( sr ) ) == 0 ) ; } static boolean isProduct ( int num ) { int cnt = 0 ; for ( int i = 2 ; cnt < 2 && i * i <= num ; ++ i ) { while ( num % i == 0 ) { num /= i ; ++ cnt ; } } if ( num > 1 ) ++ cnt ; return cnt == 2 ; } static void findNumbers ( int N ) { Vector < Integer > vec = new Vector < Integer > ( ) ; for ( int i = 1 ; i <= N ; i ++ ) { if ( isProduct ( i ) && ! isPerfectSquare ( i ) ) { vec . add ( i ) ; } } Iterator < Integer > itr = vec . iterator ( ) ; while ( itr . hasNext ( ) ) { System . out . print ( itr . next ( ) + " ▁ " ) ; } } public static void main ( String [ ] args ) { int N = 30 ; findNumbers ( N ) ; } }