Check if a large number is divisible by 6 or not

Given a number, the task is to check if a number is divisible by 6 or not. The input number may be large and it may not be possible to store even if we use long long int.

Examples:

Input  : n = 2112
Output : Yes

Input : n = 1124
Output : No

Input  : n = 363588395960667043875487
Output : No



Since input number may be very large, we cannot use n % 6 to check if a number is divisible by 8 or not, especially in languages like C/C++. The idea is based on following fact.

A number is divisible by 6 it's divisible by 2 and 3. 
a)  A number is divisible by 2 if its last digit is divisible by 2.
b)  A number is divisible by 3 if sum of digits is divisible by 3.

Below is the implementation based on above steps.

C++

// C++ program to find if a number is divisible by
// 6 or not
#include<bits/stdc++.h>
using namespace std;
  
// Function to find that number divisble by 6 or not
bool check(string str)
{
    int n = str.length();
  
    // Return false if number is not divisible by 2.
    if ((str[n-1]-'0')%2 != 0)
       return false;
  
    // If we reach here, number is divisible by 2.
    // Now check for 3.
  
    // Compute sum of digits
    int digitSum = 0;
    for (int i=0; i<n; i++)
        digitSum += (str[i]-'0');
  
    // Check if sum of digits is divisible by 3
    return (digitSum % 3 == 0);
}
  
// Driver code
int main()
{
    string str = "1332";
    check(str)?  cout << "Yes" : cout << "No ";
    return 0;
}

Java

// Java program to find if a number is
// divisible by 6 or not
class IsDivisible
{
    // Function to find that number divisble by 6 or not
    static boolean check(String str)
    {
        int n = str.length();
       
        // Return false if number is not divisible by 2.
        if ((str.charAt(n-1) -'0')%2 != 0)
           return false;
       
        // If we reach here, number is divisible by 2.
        // Now check for 3.
       
        // Compute sum of digits
        int digitSum = 0;
        for (int i=0; i<n; i++)
            digitSum += (str.charAt(i)-'0');
       
        // Check if sum of digits is divisible by 3
        return (digitSum % 3 == 0);
    }
      
    // main function
    public static void main (String[] args) 
    {
        String str = "1332";
        if(check(str))
            System.out.println("Yes");
        else
            System.out.println("No");
    }

Python3

# Python 3 program to find 
# if a number is divisible
# by 6 or not
  
# Function to find that number 
# is divisible by 6 or not
def check(st) :
    n = len(st)
      
      
    # Return false if number
    # is not divisible by 2.
    if (((int)(st[n-1])%2) != 0) :
        return False
   
    # If we reach here, number 
    # is divisible by 2. Now
    # check for 3.
   
    # Compute sum of digits
    digitSum = 0
    for i in range(0, n) :
        digitSum = digitSum + (int)(st[i])
   
    # Check if sum of digits
    # is divisible by 3
    return (digitSum % 3 == 0)
  
  
# Driver code
st = "1332"
if(check(st)) :
    print("Yes")
else :
    print("No ")
      
# This article is contributed by Nikita Tiwari.

C#

// C# program to find if a number is
// divisible by 6 or not
using System;
  
class GFG {
      
    // Function to find that number
    // divisble by 6 or not
    static bool check(String str)
    {
        int n = str.Length;
      
        // Return false if number is
        // not divisible by 2.
        if ((str[n-1] -'0') % 2 != 0)
            return false;
      
        // If we reach here, number is
        // divisible by 2.
        // Now check for 3.
      
        // Compute sum of digits
        int digitSum = 0;
        for (int i = 0; i < n; i++)
            digitSum += (str[i] - '0');
      
        // Check if sum of digits is
        // divisible by 3
        return (digitSum % 3 == 0);
    }
      
    // main function
    public static void Main () 
    {
        String str = "1332";
          
        if(check(str))
            Console.Write("Yes");
        else
            Console.Write("No");
    }
}
  
// This code is contributed by parashar.

PHP

<?php
// PHP program to find if a 
// number is divisible by
// 6 or not
  
// Function to find that number 
// divisble by 6 or not
function check($str)
{
    $n = strlen($str);
  
    // Return false if number is
    // not divisible by 2.
    if (($str[$n - 1] - '0') % 2 != 0)
    return false;
  
    // If we reach here, number 
    // is divisible by 2.
    // Now check for 3.
    // Compute sum of digits
    $digitSum = 0;
    for ($i = 0; $i < $n; $i++)
        $digitSum += ($str[$i] - '0');
  
    // Check if sum of digits
    // is divisible by 3
    return ($digitSum % 3 == 0);
}
  
    // Driver code
    $str = "1332";
    if(check($str))
        echo "Yes" ;
    else
        echo " No ";
    return 0;
  
// This code is contributed by nitin mittal.
?>


Output:

Yes

This article is contributed by DANISH_RAZA . 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.

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Improved By : parashar, nitin mittal




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