HackerRank Java Interface problem solution

In this HackerRank Java Interface problem in a java programming language, You are given an interface AdvancedArithmetic which contains a method signature int divisor_sum(int n). You need to write a class called MyCalculator which implements the interface.

HackerRank Java Interface problem solution.

import java.util.*;
interface AdvancedArithmetic{
  int divisor_sum(int n);
}

//Write your code here
class MyCalculator implements AdvancedArithmetic {
    public int divisor_sum(int n) {
        if (n <= 1) { return n; }

        int res = n + 1;
        for (int i = 2; i < n; i++) {
            if (n % i == 0) {
                res += i;
            }
        }

        return res;
    }
}

class Solution{
    public static void main(String []args){
        MyCalculator my_calculator = new MyCalculator();
        System.out.print("I implemented: ");
        ImplementedInterfaceNames(my_calculator);
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        System.out.print(my_calculator.divisor_sum(n) + "\n");
        sc.close();
    }
    /*
     *  ImplementedInterfaceNames method takes an object and prints the name of the interfaces it implemented
     */
    static void ImplementedInterfaceNames(Object o){
        Class[] theInterfaces = o.getClass().getInterfaces();
        for (int i = 0; i < theInterfaces.length; i++){
            String interfaceName = theInterfaces[i].getName();
            System.out.println(interfaceName);
        }
    }
}

Second solution

import java.util.*;
interface AdvancedArithmetic{
  int divisor_sum(int n);
}

class MyCalculator implements AdvancedArithmetic{
    int sum = 0;
    public int divisor_sum(int n){
        for(int i=1;i<=(n+1)/2;i++){
            if(n%i==0){
                sum+=i;
            }
        }
        if(n==1){
            return 1;
        }
        return (sum+n);
    }
}

class Solution{
    public static void main(String []args){
        MyCalculator my_calculator = new MyCalculator();
        System.out.print("I implemented: ");
        ImplementedInterfaceNames(my_calculator);
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        System.out.print(my_calculator.divisor_sum(n) + "\n");
        sc.close();
    }
    /*
     *  ImplementedInterfaceNames method takes an object and prints the name of the interfaces it implemented
     */
    static void ImplementedInterfaceNames(Object o){
        Class[] theInterfaces = o.getClass().getInterfaces();
        for (int i = 0; i < theInterfaces.length; i++){
            String interfaceName = theInterfaces[i].getName();
            System.out.println(interfaceName);
        }
    }
}

Third solution

import java.util.*;
interface AdvancedArithmetic {
 public abstract int divisorSum(int n);
}

//Solution starts
class MyCalculator implements AdvancedArithmetic {
 public int divisor_sum(int n) {
  int ans = 0;
  for (int i = 1; i <= n; i++) {
   if (n % i == 0) ans += i;
  }
  return ans;
 }
}
//Solution ends


class Solution {

 public static void main(String[] argh) {
   MyCalculator my_calculator = new MyCalculator();
   System.out.print("I implemented: ");
   ImplementedInterfaceNames(my_calculator);
   Scanner sc = new Scanner(System.in);
   int n = sc.nextInt();
   System.out.print(my_calculator.divisorSum(n) + "\n");

  }
  /*
   *  ImplementedInterfaceNames method takes an object and prints the name of the interfaces it implemented
   */
 static void ImplementedInterfaceNames(Object o) {

  Class[] theInterfaces = o.getClass().getInterfaces();
  for (int i = 0; i < theInterfaces.length; i++) {
   String interfaceName = theInterfaces[i].getName();
   System.out.println(interfaceName);
  }
 }
}