Skip to content
Related Articles

Related Articles

Improve Article

Find a value whose XOR with given number is maximum

  • Difficulty Level : Basic
  • Last Updated : 28 Apr, 2021
Geek Week

Given a value X, the task is to find the number Y which will give maximum value possible when XOR with X. 
(Assume X to be 8 bits) Maximum possible value of X and Y is 255.
Examples: 
 

Input:  X = 2
Output: 253
Binary Representation of X = 00000010
Binary Representation of Y = 11111101
Maximum XOR value: 11111111

Input:  X = 200
Output: 55

 

Approach: In order to ensure the maximum value of XOR, we need to set all those bits ON which are OFF in X. So for that, Y should have all bits ON which are OFF in X and OFF which are ON in X as (0^1 = 1 and 1^0 = 1). So Y should be the 1’s complement representation of X. 
Below is the implementation of the above approach: 
 

C++




// C++ implementation of the above approach
#include <bits/stdc++.h>
using namespace std;
 
// Function To Calculate Answer
int calculate(int X)
{
    // Find number of bits in the given integer
    int number_of_bits = 8;
 
    // XOR the given integer with poe(2,
    // number_of_bits-1 and print the result
    return ((1 << number_of_bits) - 1) ^ X;
}
 
// Driver Code
int main()
{
    int X = 4;
 
    cout << "Required Number is : "
         << calculate(X) << endl;
 
    return 0;
}

Java




// Java implementation of the above approach
 
import java.io.*;
 
class GFG {
     
// Function To Calculate Answer
static int calculate(int X)
{
    // Find number of bits in the given integer
    int number_of_bits = 8;
 
    // XOR the given integer with poe(2,
    // number_of_bits-1 and print the result
    return ((1 << number_of_bits) - 1) ^ X;
}
 
// Driver Code
 
 
    public static void main (String[] args) {
        int X = 4;
 
    System.out.println( "Required Number is : "
        +calculate(X));
    }
}
// This code is contributed by shs..

Python3




# Python3 implementation of the above approach
 
# Function To Calculate Answer
def calculate(X):
  
    # Find number of bits in the given integer
    number_of_bits = 8
   
    # XOR the given integer with poe(2,
    # number_of_bits-1 and print the result
    return ((1 << number_of_bits) - 1) ^ X
   
# Driver Code
if __name__ == "__main__":
  
    X = 4
    print("Required Number is:", calculate(X))
   
# This code is contributed by Rituraj Jain

C#




// C# implementation of the above approach
using System;
 
class GFG
{
     
// Function To Calculate Answer
static int calculate(int X)
{
    // Find number of bits in
    // the given integer
    int number_of_bits = 8;
 
    // XOR the given integer with poe(2,
    // number_of_bits-1 and print the result
    return ((1 << number_of_bits) - 1) ^ X;
}
 
// Driver Code
public static void Main ()
{
    int X = 4;
 
    Console.WriteLine("Required Number is : " +
                                 calculate(X));
}
}
 
// This code is contributed by shs..

PHP




<?php
// PHP implementation of the
// above approach
 
// Function To Calculate Answer
function calculate($X)
{
    // Find number of bits in
    // the given integer
    $number_of_bits = 8;
 
    // XOR the given integer with
    // poe(2, number_of_bits-1 and
    // print the result
    return ((1 << $number_of_bits) - 1) ^ $X;
}
 
// Driver Code
$X = 4;
 
echo "Required Number is : " .
      calculate($X) . "\n";
 
// This code is contributed
// by Akanksha Rai
?>

Javascript




<script>
 
// Javascript implementation of the above approach
 
// Function To Calculate Answer
function calculate(X)
{
    // Find number of bits in the given integer
    let number_of_bits = 8;
 
    // XOR the given integer with poe(2,
    // number_of_bits-1 and print the result
    return ((1 << number_of_bits) - 1) ^ X;
}
 
// Driver Code
    let X = 4;
 
    document.write("Required Number is : "
         + calculate(X) + "<br>");
 
</script>
Output: 
Required Number is : 251

 

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.




My Personal Notes arrow_drop_up
Recommended Articles
Page :