Count Hexadecimal Number

Given a range [L, R]. The task is to find the total number of Hexadecimal alphabets that are required to write every number in the range.
Hexadecimal alphabets are the alphabets in the range [A, F] which are required to represent decimal numbers from the range [10, 15]

Examples:

Input: L = 10, R = 15
Output: 6
All the numbers from 10 to 15 contain a hexadecimal alphabet.

Input: L = 15, R = 16
Output: 1
15 and 16 are represented in hexadecimal as F and 10 respectively.



Approach:

  1. First of all, check if num ≥ 10 and num ≤ 15. If yes then increment the count as decimal numbers from 10 to 15 contain a hexadecimal alphabet.
  2. If num > 15 than update the number as num = num % 16. If it is greater than 10 than increment the count.
  3. Repeat 2nd step till number (for every number) is greater than 0.

Below is the implementation of the above approach:

C++

filter_none

edit
close

play_arrow

link
brightness_4
code

// C++ implementation of the approach
#include <bits/stdc++.h>
using namespace std;
  
// Function that will count
// total hexadecimal alphabet
int countHexadecimal(int L, int R)
{
    int count = 0;
    for (int i = L; i <= R; i++) {
  
        // All the numbers from 10 to 15
        // contain a hexadecimal alphabet
        if (i >= 10 && i <= 15)
            count++;
  
        // If i > 15 then perform mod by 16 repeatedly
        // till the number is > 0
        // If number % 16 > 10 then increase count
        else if (i > 15) {
            int k = i;
            while (k != 0) {
                if (k % 16 >= 10)
                    count++;
                k = k / 16;
            }
        }
    }
  
    return count;
}
  
// Driver code
int main()
{
    int L = 5, R = 100;
    cout << countHexadecimal(L, R);
  
    return 0;
}

chevron_right


Java

filter_none

edit
close

play_arrow

link
brightness_4
code

// Java implementation of the approach
class GFG
{
      
// Function that will count
// total hexadecimal alphabet
static int countHexadecimal(int L, int R)
{
    int count = 0;
    for (int i = L; i <= R; i++) 
    {
  
        // All the numbers from 10 to 15
        // contain a hexadecimal alphabet
        if (i >= 10 && i <= 15)
            count++;
  
        // If i > 15 then perform mod by 16 
        // repeatedly till the number is > 0
        // If number % 16 > 10 then increase count
        else if (i > 15)
        {
            int k = i;
            while (k != 0
            {
                if (k % 16 >= 10)
                    count++;
                k = k / 16;
            }
        }
    }
  
    return count;
}
  
// Driver code
public static void main(String args[])
{
    int L = 5, R = 100;
    System.out.print(countHexadecimal(L, R));
}
}
  
// This code is contributed
// by Akanksha Rai

chevron_right


Python3

filter_none

edit
close

play_arrow

link
brightness_4
code

# Python3 implementation of the approach 
  
# Function that will count 
# total hexadecimal alphabet 
def countHexadecimal(L, R) : 
    count = 0
    for i in range(L, R + 1) :
  
        # All the numbers from 10 to 15 
        # contain a hexadecimal alphabet 
        if (i >= 10 and i <= 15) :
            count += 1
  
        # If i > 15 then perform mod by 16 
        # repeatedly till the number is > 0 
        # If number % 16 > 10 then 
        # increase count 
        elif (i > 15) :
            k = i; 
            while (k != 0) : 
                if (k % 16 >= 10) :
                    count += 1
                k = k // 16
  
    return count; 
  
# Driver code 
if __name__ == "__main__" :
    L = 5; R = 100
      
    print(countHexadecimal(L, R)); 
  
# This code is contributed by Ryuga

chevron_right


C#

filter_none

edit
close

play_arrow

link
brightness_4
code

// C# implementation of the approach
using System;
  
class GFG
{
      
// Function that will count
// total hexadecimal alphabet
static int countHexadecimal(int L, int R)
{
    int count = 0;
    for (int i = L; i <= R; i++) 
    {
  
        // All the numbers from 10 to 15
        // contain a hexadecimal alphabet
        if (i >= 10 && i <= 15)
            count++;
  
        // If i > 15 then perform mod by 16 repeatedly
        // till the number is > 0
        // If number % 16 > 10 then increase count
        else if (i > 15)
        {
            int k = i;
            while (k != 0) 
            {
                if (k % 16 >= 10)
                    count++;
                k = k / 16;
            }
        }
    }
  
    return count;
}
  
// Driver code
public static void Main()
{
    int L = 5, R = 100;
    Console.Write(countHexadecimal(L, R));
}
}
  
// This code is contributed
// by Akanksha Rai

chevron_right


PHP

= 10 && $i <= 15) $count++; // If i > 15 then perform mod by 16
// repeatedly till the number is > 0
// If number % 16 > 10 then increase count
else if ($i > 15)
{
$k = $i;
while ($k != 0)
{
if ($k % 16 >= 10)
$count++;
$k = $k / 16;
}
}
}

return $count;
}

// Driver code
$L = 5;
$R = 100;
echo countHexadecimal($L, $R);

// This code is contributed by Ita_c
?>

Output:

36


My Personal Notes arrow_drop_up

Check out this Author's contributed articles.

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.



Improved By : Ryuga, Akanksha_Rai, Ita_c