Question

How to check if the binary representation of a number is a palindrome in Java

Answer 1

public class MyClass {
    public static int reverseBits(int n) {
        int reversed = 0;

        int temp = n;
        while (temp > 0) {
            reversed = (reversed << 1) | (temp & 1);
            temp = temp >> 1;
        }
        return reversed;
    }
    public static boolean isPalindrome(int n) {
        return n == reverseBits(n);
    }
    public static void main(String args[]) {
        int n = 27;
        
        System.out.println(Integer.toBinaryString(n));
        
        System.out.println((isPalindrome(n) ? "Yes" : "No"));
    }
}




/*
run:

11011
Yes

*/

 

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Answer 2

public class MyClass {
    public static boolean isPalindrome(int n) {
        StringBuilder sb = new StringBuilder();
   
        sb.append(Integer.toBinaryString(n));
   
        sb = sb.reverse();
          
        return Integer.toBinaryString(n).equals(new String(sb));
    }
    public static void main(String args[]) {
        int n = 27;
         
        System.out.println(Integer.toBinaryString(n));
         
        System.out.println((isPalindrome(n) ? "Yes" : "No"));
    }
}
 
 
 
 
/*
run:
 
11011
Yes
 
*/

 

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Answer 3

public class MyClass {
    public static String reverse(String str) {
        return new StringBuilder(str).reverse().toString();
    }
     
    private static boolean is_binary_representation_of_number_palindrome(int num) {
        String binary = Integer.toBinaryString(num);
 
        System.out.println(binary);
 
        return binary.equals(reverse(binary));
    }
 
    public static void main(String args[]) {
        int num = 153; // 10011001
 
        if (is_binary_representation_of_number_palindrome(num)) {
            System.out.print("Palindrome");
        }
        else {
            System.out.print("Not Palindrome");
        }
    }
}
 
 
 
 
 
/*
run:
     
10011001
Palindrome
     
*/

 

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