Check if actual binary representation of a number is palindrome

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

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++

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// 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;
}

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Java














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// 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  



















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Python3














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# 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. 



















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C#














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// 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 



















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PHP














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<?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  


?> 



















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Output :


Yes



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


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