[HackerRank] Prime Checker

https://www.hackerrank.com/challenges/prime-checker/problem?isFullScreen=true

Solution

import java.io.*;
import java.lang.reflect.Method;
import java.util.*;

class Prime {
    void checkPrime(int... numbers) {
        for (int num : numbers) {
            if (isPrime(num)) {
                System.out.print(num + " ");
            }
        }

        System.out.println();
    }

    boolean isPrime(int n) {
        if (n < 2) {
            return false;
        } else if (n == 2) {
            return true;
        } else if (n % 2 == 0) {
            return false;
        }

        int sqrt = (int) Math.sqrt(n);
        for (int i = 3; i <= sqrt; i += 2) {
            if (n % i == 0) {
                return false;
            }
        }

        return true;
    }
}

public class Solution {

    public static void main(String[] args) {
        try (BufferedReader br = new BufferedReader(new InputStreamReader(System.in))) {
            int n1 = Integer.parseInt(br.readLine());
            int n2 = Integer.parseInt(br.readLine());
            int n3 = Integer.parseInt(br.readLine());
            int n4 = Integer.parseInt(br.readLine());
            int n5 = Integer.parseInt(br.readLine());

            Prime ob = new Prime();
            ob.checkPrime(n1);
            ob.checkPrime(n1, n2);
            ob.checkPrime(n1, n2, n3);
            ob.checkPrime(n1, n2 ,n3, n4, n5);

            Method[] methods = Prime.class.getDeclaredMethods();
            Set<String> set = new HashSet<>();
            boolean overload = false;

            for (int i = 0; i < methods.length; i++) {
                if (set.contains(methods[i].getName())) {
                    overload = true;
                    break;
                }

                set.add(methods[i].getName());
            }

            if (overload) {
                throw new Exception("Overloading not allowed");
            }

        } catch (Exception e) {
            System.out.println(e);
        }
    }
}