Maximum OR value of a pair in an array

Given an array arr[] of N positive elements. The task is to find the maximum bitwise OR value of a pair from the given array.
Examples:

Input: arr[] = {4, 8, 12, 16} 
Output: 28 
(12, 16) is the pair with the maximum bitwise OR. 
12 | 16 = 28

Input: arr[] = {4, 8, 16, 2} 
Output: 24 

Approach: Iterate over all the possible pairs and calculate the OR value of these pairs. Finally, print the maximum of all the values.

Below is the implementation of the above approach: 

C++

// C++ implementation of the approach
#include <bits/stdc++.h>
using namespace std;

// Function to return the maximum bitwise OR
// for any pair of the given array
int maxOR(int arr[], int n)
{

    // To store the maximum OR value
    int maxVal = 0;

    // For every possible pair
    for (int i = 0; i < n - 1; i++)
        for (int j = i + 1; j < n; j++) {

            // Update the maximum OR value
            maxVal = max(maxVal, arr[i] | arr[j]);
        }

    return maxVal;
}

// Driver code
int main()
{
    int arr[] = { 4, 8, 12, 16 };
    int n = sizeof(arr) / sizeof(arr[0]);

    cout << maxOR(arr, n);

    return 0;
}

Java

// Java implementation of the approach
class GFG {

    // Function to return the maximum bitwise OR
    // for any pair of the given array
    static int maxOR(int arr[], int n)
    {

        // To store the maximum OR value
        int maxVal = 0;

        // For every possible pair
        for (int i = 0; i < n - 1; i++)
            for (int j = i + 1; j < n; j++) {

                // Update the maximum OR value
                maxVal = Math.max(maxVal, arr[i] | arr[j]);
            }

        return maxVal;
    }

    // Driver code
    public static void main(String[] args)
    {
        int arr[] = { 4, 8, 12, 16 };
        int n = arr.length;

        System.out.println(maxOR(arr, n));
    }
}

// This code is contributed by AnkitRai01

Python3

# Python3 implementation of the approach

# Function to return the maximum bitwise OR
# for any pair of the given array
def maxOR(arr, n):

    # To store the maximum OR value
    maxVal = 0;

    # For every possible pair
    for i in range(n - 1):
        for j in range(i + 1, n):

            # Update the maximum OR value
            maxVal = max(maxVal, arr[i] | arr[j]);

    return maxVal;

# Driver code
if __name__ == '__main__':
    arr = [4, 8, 12, 16];
    n = len(arr);

    print(maxOR(arr, n));

# This code is contributed by 29AjayKumar

C#

// C# implementation of the approach
using System;

class GFG {

    // Function to return the maximum bitwise OR
    // for any pair of the given array
    static int maxOR(int[] arr, int n)
    {

        // To store the maximum OR value
        int maxVal = 0;

        // For every possible pair
        for (int i = 0; i < n - 1; i++)
            for (int j = i + 1; j < n; j++) {

                // Update the maximum OR value
                maxVal = Math.Max(maxVal, arr[i] | arr[j]);
            }

        return maxVal;
    }

    // Driver code
    static public void Main()
    {
        int[] arr = { 4, 8, 12, 16 };
        int n = arr.Length;

        Console.Write(maxOR(arr, n));
    }
}

// This code is contributed by ajit.

Javascript

<script>
    // Javascript implementation of the approach

      // Function to return the maximum bitwise OR
    // for any pair of the given array
    function maxOR(arr, n)
    {

        // To store the maximum OR value
        let maxVal = 0;

        // For every possible pair
        for (let i = 0; i < n - 1; i++)
            for (let j = i + 1; j < n; j++) {

                // Update the maximum OR value
                maxVal = Math.max(maxVal, arr[i] | arr[j]);
            }

        return maxVal;
    }

    let arr = [ 4, 8, 12, 16 ];
    let n = arr.length;

    document.write(maxOR(arr, n));
</script>

Output:

28

Time Complexity: O(n*n)
Auxiliary Space: O(1)