Special two digit number

A special two-digit number is a number such that when the sum of the digits of the number is added to the product of its digits, the result is equal to the original two-digit number. 

Examples :

input : 59.
output : 59 is a Special Two-Digit Number
Explanation:
Sum of digits = 5 + 9 = 14
Product of its digits = 5 x 9 = 45
Sum of the sum of digits 
and product of digits = 14 + 45 = 59

input: 29
output: 29 is a Special Two-digit Number
Explanation:
Sum of digits = 9 + 2 = 11
Product of digits = 9 * 2 = 18
Sum of the sum of digits 
and product of digits = 11 + 18 = 29

Approach:

Extract the first and last digit of the number and add and multiply the digits separately. Then, add the sum and product of the digits of the two-digit number and compare it to the original number. If they are same, then it is a Special Two-Digit Number, else it is not.

Below is the implementation of above approach: 

C++

// CPP program to find if number is
// a Special Two-Digit number or not
#include<bits/stdc++.h>
using namespace std;

// function to find if number
// is special or not
void specialNumber(int n)
{
    // Checking whether entered
    // number is 2 digit or not
    if (n < 10 || n > 99)
        cout << "Invalid Input! Number"
             << " should have 2 digits only";
    else
    {
        // Finding the first digit
        int first = n / 10;

        // Finding the last digit
        int last = n % 10;

        // Finding the sum of
        // the digits
        int sum = first + last;

        // Finding the product
        // of the digits
        int pro = first * last;

        if ((sum + pro) == n)
        {
            cout << n <<" is a Special "
                 << "Two-Digit Number";
        }
        else
        {
            cout << n << " is Not a "
                 << "Special Two-Digit Number";
        }
    }
}

// Driver Code
int main()
{
    int n = 59;

    // function calling
    specialNumber(n);
    return 0;
}

Java

// Java program to find if number is
// a Special Two-Digit number or not
import java.io.*;

class GFG
{
    // function to find if number
    // is special or not
    static void specialNumber(int n)
    {
        // Checking whether entered
        // number is 2 digit or not
        if(n < 10 || n > 99)
            System.out.println("Invalid Input! " +
                           "Number should have " +
                                 "2 digits only");
        else
        {
            // Finding the first digit
            int first = n / 10;

            // Finding the last digit
            int last = n % 10;

            // Finding the sum
            // of the digits
            int sum = first + last;

            // Finding the product
            // of the digits
            int pro = first * last;

            if((sum + pro) == n)
            {
                System.out.println(n + " is a Special" +
                                   " Two-Digit Number");
            }
            else
            {
                System.out.println(n +" is Not a Special" +
                                      " Two-Digit Number");
            }
        }
    }

    // Driver Code
    public static void main(String args[])
    {
        int n = 59;
        specialNumber(n);
    }
}

Python3

# Python3 code to find if
# number is a Special
# Two-Digit number or not

# Function to find if number
# is special or not
def specialNumber(n):

    # Checking whether entered
    # number is 2 digit or not
    if (n < 10 or n > 99):
        print("Invalid Input! Number",
              " should have 2 digits only")
    else:

        # Finding the first digit
        first = n // 10

        # Finding the last digit
        last = n % 10

        # Finding the sum
        # of the digits
        sum = first + last

        # Finding the product
        # of the digits
        pro = first * last

        if ((sum + pro) == n):

            print(n ," is a Special ",
                   "Two-Digit Number")
        else:

            print(n , " is Not a ",
                "Special Two-Digit Number")

# Driver code
n = 59
specialNumber(n)

# This code is contributed
# by Anant Agarwal.

C#

// C# program to find if number is
// a Special Two-Digit number or not
using System;

class GFG
{

    // function to find if number
    // is special or not
    static void specialNumber(int n)
    {

        // Checking whether entered
        // number is 2 digit or not
        if(n < 10 || n > 99)
            Console.WriteLine("Invalid Input!" +
                          " Number should have"+
                              " 2 digits only");
        else
        {

            // Finding the first digit
            int first = n / 10;

            // Finding the last digit
            int last = n % 10;

            // Finding the sum
            // of the digits
            int sum = first + last;

            // Finding the product
            // of the digits
            int pro = first * last;

            if((sum + pro) == n)
            {
                Console.WriteLine(n + " is a Special"+
                                 " Two-Digit Number");
            }
            else
            {
                Console.WriteLine(n + " is Not a Special" +
                                      " Two-Digit Number");
            }
        }
    }

    // Driver Code
    public static void Main()
    {
        int n = 59;

        specialNumber(n);
    }
}

// This code is contributed by vt_m.

PHP

<?php
// PHP program to find if number is
// a Special Two-Digit number or not

// function to find if number
// is special or not

function specialNumber($n)
{
    // Checking whether entered
    // number is 2 digit or not
    if ($n < 10 || $n > 99)
        echo "Invalid Input!
              Number should
              have 2 digits only";
    else
    {
        // Finding the first digit
        $first = $n / 10;

        // Finding the last digit
        $last = $n % 10;

        // Finding the sum
        // of the digits
        $sum = $first + $last;

        // Finding the product
        // of the digits
        $pro = $first * $last;

        if (($sum + $pro) != $n)
        {
            echo $n ," is a Special " .
                    "Two-Digit Number";
        }
        else
        {
            echo $n, " is Not a Special".
                     " Two-Digit Number";
        }
    }
}

// Driver Code
$n = 59;

// function calling
specialNumber($n);

// This code is contributed by ajit.
?>

Javascript

<script>

      // JavaScript program to find if number is
      // a Special Two-Digit number or not

      // function to find if number
      // is special or not
      function specialNumber(n) {
        // Checking whether entered
        // number is 2 digit or not
        if (n < 10 || n > 99)
          document.write(
            "Invalid Input! Number" +
            " should have 2 digits only"
          );
        else {
          // Finding the first digit
          var first = parseInt(n / 10);

          // Finding the last digit
          var last = parseInt(n % 10);

          // Finding the sum of
          // the digits
          var sum = first + last;

          // Finding the product
          // of the digits
          var pro = first * last;

          if (sum + pro === n) {
            document.write(
            n + (" is a Special " +
            "Two-Digit Number")
            );
          } else {
            document.write(
            n +
            (" is Not a " + "Special Two-Digit Number")
            );
          }
        }
      }

      // Driver Code
      var n = 59;
      // function calling
      specialNumber(n);

</script>

Output

59 is a Special Two-Digit Number

Time Complexity: O(1), As we are performing constant time operations.
Auxiliary Space: O(1), As constant extra space is used.