Maximum AND Value [TC: O(32*N); SC: O(1)]

max-AND-value.cpp

// Problem Link: https://practice.geeksforgeeks.org/problems/maximum-and-value2637/1
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 maxEle = INT_MIN;
  for(int i = 0; i < n; ++i)
    maxEle = max(maxEle, arr[i]);
  
  int MSB = 0;
  for(int i = 0; i < 32; ++i)
    if((maxEle >> i) & 1)
      MSB = i;
  
  int res = 0, count;
  for(int bit = MSB; bit >= 0; --bit) {
    count = checkBit(res | (1 << bit), arr, n);
    if(count >= 2) res |= (1 << bit);
  }
  return res;
}

Problem Link