index.php

<!-- 
Given an integer array nums and an integer k, return the number of pairs (i, j) where i < j such that |nums[i] - nums[j]| == k.
The value of |x| is defined as:
x if x >= 0.
-x if x < 0.


Example 1
Input: nums = [1,2,2,1], k = 1
Output: 4
Explanation: The pairs with an absolute difference of 1 are:
- [1,2,2,1]
- [1,2,2,1]
- [1,2,2,1]
- [1,2,2,1]


Example 2:
Input: nums = [1,3], k = 3
Output: 0
Explanation: There are no pairs with an absolute difference of 3.


Example 3:
Input: nums = [3,2,1,5,4], k = 2
Output: 3
Explanation: The pairs with an absolute difference of 2 are:
- [3,2,1,5,4]
- [3,2,1,5,4]
- [3,2,1,5,4]


Constraints:
1 <= nums.length <= 200
1 <= nums[i] <= 100
1 <= k <= 99 -->


<?php

    function countAbsolutePairs($num, $k){
         
        $count =0;
        $length= count($num);

        for($i= 0; $i<$length; $i++){
            for($j= $i + 1; $j< $length; $j++){
                $absoluteValue= abs($num[$i]-$num[$j]);

                if($k== $absoluteValue){
                    $count++;
                }
            }
        }

        return $count;
    }

    echo countAbsolutePairs([1,2,2,1], 1);

?>