# Maximum OR value of a pair in an Array | Set 2

• Last Updated : 20 Apr, 2021

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[] = {3, 6, 8, 16}
Output: 24
Explanation:
The pair giving maximum OR value is (8, 16)
8|16 = 24
Input: arr[] = {8, 7, 3, 12}
Output: 15
Explanation:
There are more than one pair giving us the maximum OR value.
8|7 = 15

Naive Approach: Refer to Maximum OR value of a pair in an array for the naive approach.
Efficient Approach: In this article, we will discuss an optimized solution for the given problem.
Follow the steps below to solve the problem:

• Find the largest element from the array.
• Perform Bitwise OR between the largest element and the remaining array elements one by one. This is because the arrangement of set bits in the largest element will contribute to maximum OR value possible from array elements.
• Print the maximum OR value obtained performing the above step.

Below is the implementation of the above approach:

## C++

 `// C++ implementation of` `// the approach above`   `#include ` `using` `namespace` `std;`   `// Function to return the maximum` `// bitwise OR for any pair of the` `// given array in O(n) time complexity.` `int` `maxOR(``int` `arr[], ``int` `n)` `{` `    ``// Find the maximum` `    ``// element in the array` `    ``int` `max_value` `        ``= *max_element(arr,` `                       ``arr + n);`   `    ``// Stores the maximum` `    ``// OR value` `    ``int` `ans = 0;`   `    ``// Traverse the array and` `    ``// perform Bitwise OR` `    ``// between every array element` `    ``// with the maximum element` `    ``for` `(``int` `i = 0; i < n; i++) {` `        ``ans = max(ans, (max_value` `                        ``| arr[i]));` `    ``}` `    ``return` `ans;` `}`   `// Driver Code` `int` `main()` `{` `    ``int` `arr[] = { 3, 6, 8, 16 };` `    ``int` `n = ``sizeof``(arr)` `            ``/ ``sizeof``(arr);`   `    ``cout << maxOR(arr, n);`   `    ``return` `0;` `}`

## Java

 `// Java implementation of` `// the approach above` `import` `java.util.Arrays;` `class` `GFG{` `    `  `// Function to return the maximum` `// bitwise OR for any pair of the` `// given array in O(n) time complexity.` `static` `int` `maxOR(``int` `[]arr, ``int` `n)` `{` `    ``// Find the maximum` `    ``// element in the array` `    ``int` `max_value = Arrays.stream(arr).max().getAsInt();`   `    ``// Stores the maximum` `    ``// OR value` `    ``int` `ans = ``0``;`   `    ``// Traverse the array and` `    ``// perform Bitwise OR` `    ``// between every array element` `    ``// with the maximum element` `    ``for` `(``int` `i = ``0``; i < n; i++) ` `    ``{` `        ``ans = Math.max(ans, (max_value | arr[i]));` `    ``}` `    ``return` `ans;` `}`   `// Driver Code` `public` `static` `void` `main(String[] args)` `{` `    ``int` `arr[] = ``new` `int``[]{ ``3``, ``6``, ``8``, ``16` `};` `    ``int` `n = ``4``;`   `    ``System.out.print(maxOR(arr, n));` `}` `}`   `// This code is contributed by Ritik Bansal`

## Python3

 `# Python3 implementation of ` `# the approach above `   `# Function to return the maximum` `# bitwise OR for any pair of the` `# given array in O(n) time complexity.` `def` `maxOR(arr, n):`   `    ``# Find the maximum` `    ``# element in` `    ``max_value ``=` `max``(arr)` `    `  `    ``# Stores the maximum` `    ``# OR value the array` `    ``ans ``=` `0`   `    ``# Traverse the array and` `    ``# perform Bitwise OR` `    ``# between every array element` `    ``# with the maximum element` `    ``for` `i ``in` `range``(n): ` `        ``ans ``=` `max``(ans, (max_value | arr[i]))` `    `  `    ``return` `ans`   `# Driver Code` `if` `__name__ ``=``=` `"__main__"``:` `    `  `    ``arr ``=` `[ ``3``, ``6``, ``8``, ``16` `]` `    ``n ``=` `len``(arr)`   `    ``print``(maxOR(arr, n))`   `# This code is contributed by jana_sayantan`

## C#

 `// C# implementation of` `// the approach above` `using` `System;` `using` `System.Linq;`   `class` `GFG{` `    `  `// Function to return the maximum` `// bitwise OR for any pair of the` `// given array in O(n) time complexity.` `static` `int` `maxOR(``int` `[]arr, ``int` `n)` `{` `    `  `    ``// Find the maximum` `    ``// element in the array` `    ``int` `max_value = arr.Max();`   `    ``// Stores the maximum` `    ``// OR value` `    ``int` `ans = 0;`   `    ``// Traverse the array and` `    ``// perform Bitwise OR` `    ``// between every array element` `    ``// with the maximum element` `    ``for``(``int` `i = 0; i < n; i++) ` `    ``{` `        ``ans = Math.Max(ans, (max_value | ` `                             ``arr[i]));` `    ``}` `    ``return` `ans;` `}`   `// Driver Code` `public` `static` `void` `Main(String[] args)` `{` `    ``int` `[]arr = { 3, 6, 8, 16 };` `    ``int` `n = 4;`   `    ``Console.Write(maxOR(arr, n));` `}` `}`   `// This code is contributed by 29AjayKumar`

## Javascript

 ``

Output:

`24`

Time Complexity: O(N)
Auxiliary Space: O(1)

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