/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		// your code goes here
	}
}
 
class Solution {
    public int countKDifference(int[] nums, int k) {
        HashMap<Integer , Integer> map =  new HashMap<>();
        int n = nums.length;
        int pairs = 0;
        for(int i  = 0 ; i< n ; i++){
            int curr = nums[i];
            int req1 = curr - k;
            int req2 = curr + k;
            int type1 = 1*map.getOrDefault(req1 , 0);
            int type2 = 1*map.getOrDefault(req2 , 0);
            pairs+=(type1 + type2);
            map.put(curr , map.getOrDefault(curr , 0) + 1); 
        }
        return pairs;
    }
}

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