Question

How to count all distinct pairs from array with specific difference between them in C++

Answer 1

#include <iostream> 

int countPairsWithSpecificDifference(int arr[], int size, int difference) { 
    int count = 0; 
      
    for (int i = 0; i < size; i++) {        
        for (int j = i + 1; j < size; j++) {
            if (arr[i] - arr[j] == difference || arr[j] - arr[i] == difference) {
                  count++; 
            }
        }
    } 
    return count; 
} 
  
int main() 
{ 
    int arr[] = {25, 16, 8, 12, 20, 17, 0, 4, 21, 26}; 
    int difference = 4; 

    // 7 pairs with difference 4: {25, 21}, {16, 12}, {16, 20}, {8, 12}, {8, 4}, {17, 21} {0, 4} 

    int size = sizeof(arr)/sizeof(arr[0]); 

    std::cout << countPairsWithSpecificDifference(arr, size, difference); 
    
    return 0; 
} 




/*
run:
  
7
  
*/

 

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