In a C program, print out the pair of elements with the largest AND value in an array

According to the question, we are given an array containing n positive integers, and we need to find the pair with the maximum AND value from the array.

Example

Input: arr[] = { 4, 8, 12, 16 }
Output: pair = 8 12
The maximum and value= 8

Input:arr[] = { 4, 8, 16, 2 }
Output: pair = No possible AND
The maximum and value = 0

The method of finding the maximum AND value is similar to finding the maximum AND value in an array. The program must find the pair of elements that results in the resulting AND value. In order to find these elements, just iterate through the entire array and find the AND value of each element with the maximum AND value (result) you get, if arr[i] & result == result, it means arr[i] is the maximum AND value that will be generated Elements of AND values. Furthermore, we should print "impossible" in case the maximum AND value (result) is zero.

Algorithm

int checkBit(int pattern, int arr[], int n)
START
STEP 1: DECLARE AND INITIALIZE count AS 0
STEP 2: LOOP FOR i = 0 AND i < n AND i++
   IF (pattern & arr[i]) == pattern THEN,
      INCREMENT count BY 1
STEP 3: RETURN count
STOP
int maxAND(int arr[], int n)
START
STEP 1: DECLARE AND INITIALIZE res = 0 AND count
STEP 2: LOOP FOR bit = 31 AND bit >= 0 AND bit--
   count = GOTO FUNCTION checkBit(res | (1 << bit), arr,n)
   IF count >= 2 THEN,
      res |= (1 << bit);
   END IF
   IF res == 0
      PRINT "no possible AND&rdquo;
   ELSE
      PRINT "Pair with maximum AND= "
   count = 0;
   LOOP FOR int i = 0 AND i < n && count < 2 AND i++
      IF (arr[i] & res) == res THEN,
         INCREMENT count BY 1
         PRINT arr[i]
      END IF
   END FOR
END FOR
RETURN res
STOP

Example

is translated as:

Example

#include <stdio.h>
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;
   for (int bit = 31; bit >= 0; bit--) {
      count = checkBit(res | (1 << bit), arr, n);  
      if (count >= 2)
         res |= (1 << bit);
   }
   if (res == 0) //if there is no pair available
      printf("no possible and</p><p>");
   else { //Printing the pair available
      printf("Pair with maximum AND= ");
      count = 0;
      for (int i = 0; i < n && count < 2; i++) {
         // incremnent count value after
         // printing element
         if ((arr[i] & res) == res) {
            count++;
            printf("%d ", arr[i]);
         }
      }
   }
   return res;
}
int main(int argc, char const *argv[]){
   int arr[] = {5, 6, 2, 8, 9, 12};
   int n = sizeof(arr)/sizeof(arr[0]);
   int ma = maxAND(arr, n);
   printf("</p><p>The maximum AND value= %d ", ma);
   return 0;
}

Output

If we run the above program, it will generate the following Output −

pair = 8 9
The maximum and value= 8

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