Help in verifying Time Complexity of the code

1

Problem: Maximum AND value of a pair in an array

Problem Link:Maximum AND Value | Practice | GeeksforGeeks

Can someone tell me

I> how the time complexity of the solution code is O(n * log(m)) where m is the maximum element from the array and n is the size of the array.???

Solution provide by geeks :

// CPP Program to find maximum XOR value of a pair
#include<bits/stdc++.h>
using namespace std;

// Utility function to check number of elements
// having set msb as of pattern
int checkBit(int pattern, int arr[], int n)
{
	int count = 0;
	for (int i = 0; i < n; i++)
		if ((pattern & arr[i]) == pattern)
			count++;
	return count;
}

// Function for finding maximum and value pair
int maxAND (int arr[], int n)
{
	int res = 0, count;

	// iterate over total of 30bits from msb to lsb
	for (int bit = 31; bit >= 0; bit--)
	{
		// find the count of element having set msb
		count = checkBit(res | (1 << bit),arr,n);

		// if count >= 2 set particular bit in result
		if ( count >= 2 )	
			res |= (1 << bit);	
	}

	return res;
}

// Driver function
int main()
{
	int arr[] = {4, 8, 6, 2};
	int n = sizeof(arr)/sizeof(arr[0]);
	cout << "Maximum AND Value = " << maxAND(arr,n);
	return 0;
}