查找其给定数的XOR最大值的值

给定值X，任务是找到与Y进行XOR运算时将给出最大值的数字Y。
(假定X为8位)X和Y的最大可能值为255。
例子：

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

Input:  X = 200
Output: 55

方法：为了确保XOR的最大值，我们需要将X中所有OFF的位设置为ON。为此，Y应该将X中OFF的所有位ON和X中OFF的所有位设为( 0 ^ 1 = 1和1 ^ 0 = 1)。因此，Y应该是X的1的补码表示。
下面是上述方法的实现：

C++

// C++ implementation of the above approach
#include 
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..

Javascript

 
// 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>");
 

输出：

Required Number is : 251