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  1. #include<bits/stdc++.h>
  2. using namespace std;
  3.  
  4. main(){
  5.     int n,k;
  6.     cin>>n>>k;
  7.     vector<int>v(n);
  8.     unordered_map<int,int>mp;
  9.     for(auto &it:v){
  10.         cin>>it;
  11.         mp[it]++;
  12.     }
  13.     int cnt=0;
  14.     for(auto &it:mp){
  15.         if(k==0) cnt+=(it.second*(it.second-1))/2;
  16.         else{    
  17.         if(mp.find(it.first-k)!=mp.end()){
  18.             cnt+=mp[it.first-k]*it.second;
  19.         }
  20.         if(mp.find(it.first+k)!=mp.end()){
  21.             cnt+=mp[it.first+k]*it.second;
  22.         }
  23.         mp.erase(it.first);
  24.     }
  25.     }
  26.     cout<<cnt<<"\n";
  27. }
Success #stdin #stdout 0.01s 5280KB
comments (?)
stdin
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6 4
0 4 8 12 16 16
stdout
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2
https://ideone.com/XQPBG2
language:
C++14 (gcc 8.3)
created:
5 days ago
visibility:
public

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