Basics & Puzzles

Prime number is a number which is divisible by itself. We can write this program in multiple ways but it will reduce the performance for  larger numbers. Here we define one of faster and optimised way to check if number is prime or not. public boolean isPrime( int value) {           if(value == 2)                    return true;            if (value % 2 == 0)                    return false ;          for ( int j = 3; j <= Math.sqrt(value); j+=2) {                if (value % j == 0) {                        return false ;               }         }         return true ; } In this...

Two boys want to cross a river. Only one boat is present on the riverside that can carry only one person at a time. However, they still manage to cross the river. How is it possible ?