给定范围内的最大按位与对(X，Y)，使得X和Y可以相同

在给定范围[L，R]的情况下，任务是找到一个不一定是对的(X，Y)。找到所选整数的按位与的最大可能值。
例子：

Input: L = 3, R = 7 
Output: 7 
Explanation: 
In all the possible pairs, pair (7, 7) gives the maximum value for bitwise AND.
Input: L = 54, R = 55 
Output: 55 
Explanation: 
In all the possible pairs, pair (55, 55) gives the maximum value for bitwise AND. 
 

幼稚的方法：为了解决上述问题，幼稚的方法是从L迭代到R，并检查每个可能的对的按位与，并在最后打印最大值。
时间复杂度： O(N ² )
高效方法：
为了优化上述方法，我们必须观察到，这里我们必须对L和R进行整数处理，并且必须从区间[L，R]中选择两个整数，以使它们的按位与最大。 L和R之间任意两个数字的按位与将始终始终小于或等于R。因此，如果必须从间隔中选择两个整数，则可以将整数选择为R，这是最大化按位与的唯一方法。
下面是上述方法的实现：

C

// C implementation to find the
// Maximum Bitwise AND pair (X, Y)
// from given range such that
// X and Y can be same
 
#include 
 
// Function to return the
// maximum bitwise AND
int maximumAND(int L, int R)
{
    return R;
}
 
// Driver code
int main()
{
    int l = 3;
    int r = 7;
 
    printf("%d", maximumAND(l, r));
 
    return 0;
}

C++

// C++ implementation to find the
// Maximum Bitwise AND pair (X, Y)
// from given range such that
// X and Y can be same
 
#include 
using namespace std;
 
// Function to return the
// maximum bitwise AND
int maximumAND(int L, int R)
{
    return R;
}
 
// Driver code
int main()
{
    int l = 3;
    int r = 7;
 
    cout << maximumAND(l, r);
 
    return 0;
}

Java

// Java implementation to find the
// Maximum Bitwise AND pair (X, Y)
// from given range such that
// X and Y can be same
 
class GFG {
 
    // Function to return the
    // maximum bitwise AND
    static int maximumAND(int L, int R)
    {
        return R;
    }
 
    // Driver code
    public static void main(String[] args)
    {
        int l = 3;
        int r = 7;
        System.out.print(maximumAND(l, r));
    }
}

Python3

# Python3 implementation to find the
# Maximum Bitwise AND pair (X, Y)
# from given range such that
# X and Y can be same
 
# Function to return the
# maximum bitwise AND
def maximumAND(L, R):
    return R
 
# Driver code
if __name__ == '__main__':
    l = 3
    r = 7
    print(maximumAND(l, r))

C#

// C# implementation to find the
// maximum Bitwise AND pair (X, Y)
// from given range such that
// X and Y can be same
using System;
 
class GFG{
 
// Function to return the
// maximum bitwise AND
static int maximumAND(int L, int R)
{
    return R;
}
 
// Driver code
public static void Main(String[] args)
{
    int l = 3;
    int r = 7;
     
    Console.Write(maximumAND(l, r));
}
}
 
// This code is contributed by amal kumar choubey

Javascript

 
// JavaScript implementation to find the
// Maximum Bitwise AND pair (X, Y)
// from given range such that
// X and Y can be same
 
// Function to return the
    // maximum bitwise AND
    function maximumAND(L, R)
    {
        return R;
    }
 
// Driver Code
 
        let l = 3;
        let r = 7;
        document.write(maximumAND(l, r));
 

输出：

7

时间复杂度： O(1)