Skip to content
Related Articles

Related Articles

Improve Article
Save Article
Like Article

Check if actual binary representation of a number is palindrome

  • Difficulty Level : Hard
  • Last Updated : 08 Apr, 2021

Given a non-negative integer n. The problem is to check if binary representation of n is palindrome or not. Note that the actual binary representation of the number is being considered for palindrome checking, no leading 0’s are being considered.
Examples : 
 

Input : 9
Output : Yes
(9)10 = (1001)2

Input : 10
Output : No
(10)10 = (1010)2

 

Attention reader! Don’t stop learning now. Get hold of all the important DSA concepts with the DSA Self Paced Course at a student-friendly price and become industry ready.  To complete your preparation from learning a language to DS Algo and many more,  please refer Complete Interview Preparation Course.

In case you wish to attend live classes with experts, please refer DSA Live Classes for Working Professionals and Competitive Programming Live for Students.

Approach: Following are the steps:
 



  1. Get the number obtained by reversing the bits in the binary representation of n. Refer this post. Let it be rev.
  2. If n == rev, then print “Yes” else “No”.

 

C++




// C++ implementation to check whether binary
// representation of a number is palindrome or not
#include <bits/stdc++.h>
using namespace std;
 
// function to reverse bits of a number
unsigned int reverseBits(unsigned int n)
{
    unsigned int rev = 0;
 
    // traversing bits of 'n' from the right
    while (n > 0) {
 
        // bitwise left shift 'rev' by 1
        rev <<= 1;
 
        // if current bit is '1'
        if (n & 1 == 1)
            rev ^= 1;
 
        // bitwise right shift 'n' by 1
        n >>= 1;
    }
 
    // required number
    return rev;
}
 
// function to check whether binary representation
// of a number is palindrome or not
bool isPalindrome(unsigned int n)
{
    // get the number by reversing bits in the
    // binary representation of 'n'
    unsigned int rev = reverseBits(n);
 
    return (n == rev);
}
 
// Driver program to test above
int main()
{
    unsigned int n = 9;
    if (isPalindrome(n))
        cout << "Yes";
    else
        cout << "No";
    return 0;
}

Java




// Java code  to check whether 
// binary representation of a
// number is palindrome or not
import java.util.*;
import java.lang.*;
 
public class GfG
{
    // function to reverse bits of a number
    public static long reverseBits(long n)
    {
        long rev = 0;
 
        // traversing bits of 'n'
        // from the right
        while (n > 0)
        {
            // bitwise left shift 'rev' by 1
            rev <<= 1;
 
            // if current bit is '1'
            if ((n & 1) == 1)
                rev ^= 1;
 
            // bitwise right shift 'n' by 1
            n >>= 1;
        }
 
        // required number
        return rev;
    }
 
    // function to check a number
    // is palindrome or not
    public static boolean isPalindrome(long n)
    {
        // get the number by reversing
        // bits in the  binary
        // representation of 'n'
        long rev = reverseBits(n);
 
        return (n == rev);
    }
     
    // Driver function
    public static void main(String argc[])
    {
        long n = 9;
        if (isPalindrome(n))
            System.out.println("Yes");
        else
            System.out.println("No");
    }
     
}
 
// This code is contributed by Sagar Shukla

Python3




# Python 3 implementation to check
# whether binary representation of
# a number is palindrome or not
 
# function to reverse bits of a number
def reverseBits(n) :
    rev = 0
     
  # traversing bits of 'n' from the right
  while (n > 0) :
 
     # bitwise left shift 'rev' by 1
     rev = rev << 1
 
     # if current bit is '1'
     if (n & 1 == 1) :
     rev = rev ^ 1
 
     # bitwise right shift 'n' by 1
     n = n >> 1
     
     # required number
     return rev
     
# function to check whether binary
# representation of a number is
# palindrome or not
def isPalindrome(n) :
 
    # get the number by reversing
    # bits in the binary
    # representation of 'n'
    rev = reverseBits(n)
 
    return (n == rev)
 
 
# Driver program to test above
n = 9
if (isPalindrome(n)) :
    print("Yes")
else :
    print("No")
     
# This code is contributed by Nikita Tiwari.

C#




// C# code to check whether
// binary representation of a
// number is palindrome or not
using System;
 
public class GfG
{
    // function to reverse bits of a number
    public static long reverseBits(long n)
    {
        long rev = 0;
 
        // traversing bits of 'n'
        // from the right
        while (n > 0)
        {
            // bitwise left shift 'rev' by 1
            rev <<= 1;
 
            // if current bit is '1'
            if ((n & 1) == 1)
                rev ^= 1;
 
            // bitwise right shift 'n' by 1
            n >>= 1;
        }
 
        // required number
        return rev;
    }
 
    // function to check a number
    // is palindrome or not
    public static bool isPalindrome(long n)
    {
        // get the number by reversing
        // bits in the binary
        // representation of 'n'
        long rev = reverseBits(n);
 
        return (n == rev);
    }
     
    // Driver function
    public static void Main()
    {
        long n = 9;
        if (isPalindrome(n))
            Console.WriteLine("Yes");
        else
            Console.WriteLine("No");
    }
     
}
 
// This code is contributed by vt_m

PHP




<?php
// PHP implementation to check
// whether binary representation
// of a number is palindrome or not
 
// function to reverse bits of a number
function reverseBits($n)
{
    $rev = 0;
 
    // traversing bits of 'n'
    // from the right
    while ($n > 0)
    {
 
        // bitwise left shift 'rev' by 1
        $rev <<= 1;
 
        // if current bit is '1'
        if ($n & 1 == 1)
            $rev ^= 1;
 
        // bitwise right shift 'n' by 1
        $n >>= 1;
    }
 
    // required number
    return $rev;
}
 
// function to check whether
// binary representation of a
// number is palindrome or not
function isPalindrome($n)
{
    // get the number by reversing
    // bits in the binary representation
    // of 'n'
    $rev = reverseBits($n);
 
    return ($n == $rev);
}
 
// Driver code
$n = 9;
if (isPalindrome($n))
    echo "Yes";
else
    echo "No";
return 0;
 
// This code is contributed by mits
?>

Javascript




<script>
 
// JavaScript program  to check whether 
// binary representation of a
// number is palindrome or not
 
    // function to reverse bits of a number
    function reverseBits(n)
    {
        let rev = 0;
   
        // traversing bits of 'n'
        // from the right
        while (n > 0)
        {
            // bitwise left shift 'rev' by 1
            rev <<= 1;
   
            // if current bit is '1'
            if ((n & 1) == 1)
                rev ^= 1;
   
            // bitwise right shift 'n' by 1
            n >>= 1;
        }
   
        // required number
        return rev;
    }
   
    // function to check a number
    // is palindrome or not
    function isPalindrome(n)
    {
        // get the number by reversing
        // bits in the  binary
        // representation of 'n'
        let rev = reverseBits(n);
   
        return (n == rev);
    }
 
// Driver code
 
        let n = 9;
        if (isPalindrome(n))
            document.write("Yes");
        else
            document.write("No");
 
</script>

Output : 
 

Yes

Time Complexity: O(num), where num is the number of bits in the binary representation of n.
 




My Personal Notes arrow_drop_up
Recommended Articles
Page :

Start Your Coding Journey Now!