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  1. import java.util.*;
  2. class Main{
  3.  
  4.     public static int pairs(int [] arr,int k){
  5.         HashMap<Integer,Integer> map=new HashMap<>();
  6.         int count=0;
  7.         for(int i=0;i<arr.length;i++){
  8.            if(k==0){
  9.                count+=map.getOrDefault(arr[i],0);
  10.  
  11.            }else{
  12.             count+=map.getOrDefault(arr[i]+k,0);
  13.             count+=map.getOrDefault(arr[i]-k,0);
  14.  
  15.            }
  16.             map.put(arr[i],map.getOrDefault(arr[i],0)+1);
  17.         }
  18.         return count;
  19.     }
  20.     public static void main (String[] args) {
  21.         int [] arr={5,4,3,2,1};
  22.         int k=2;
  23.        System.out.println(pairs(arr,k));
  24.     }
  25. }
Success #stdin #stdout 0.08s 52492KB
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https://ideone.com/aKyHIq
language:
Java (HotSpot 12)
created:
11 hours ago
visibility:
public

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