Count pairs with Bitwise OR as Even number in C++

C++Server Side ProgrammingProgramming

We are given an integer array and the task is to count the total number of pairs that can be formed using the given array values such that the OR operation on the pairs will result in an even number.

The truth table for OR operation is given below

ABAVB
000
101
011
111

Input − int arr[] = {2, 5, 1, 8, 9}

Output − Count of pairs with Bitwise OR as EVEN number are − 2

Explanation

a1a2a1Va2
257
213
2810
2911
515
5813
5913
189
1910
899

Approach used in the below program is as follows

  • Input an array of integer elements to form an pair

  • Calculate the size of an array pass the data to the function for further processing

  • Create a temporary variable count to store the pairs formed with OR operation as an even value.

  • Start loop FOR from i to 0 till the size of an array

  • Inside the loop, check IF arr[i] & 1 == FALSE then increment the count by 1

  • Set the count as count * (count - 1) / 2

  • Return the count

  • Print the result.

Example

 Live Demo

#include <iostream>
using namespace std;
//Count pairs with Bitwise AND as ODD number
int count_pair(int arr[], int size){
   int count = 0;
   for (int i = 0; i < size; i++){
      if(!(arr[i] & 1)){
         count++;
      }
   }
   count = count * (count - 1) / 2;
   return count;
}
int main(){
   int arr[] = {2, 5, 1, 8, 9, 2, 7};
   int size = sizeof(arr) / sizeof(arr[0]);
   cout<<"Count of pairs with Bitwise OR as Even number are: "<<count_pair(arr, size) << endl;
   return 0;
}

Output

If we run the above code it will generate the following output- −

Count of pairs with Bitwise OR as Even number are: 3
raja
Published on 31-Aug-2020 09:18:24
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