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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.     unordered_map<int,int>mp;
  8.     int a,cnt=0;
  9.     for(int i=0;i<n;i++){
  10.         cin>>a;
  11.         if(mp.find(a-k)!=mp.end()){
  12.             cnt+=mp[a-k];
  13.         }
  14.         if(mp.find(a+k)!=mp.end()){
  15.             cnt+=mp[a+k];
  16.         }
  17.         mp[a]++;
  18.     }
  19.     if(k==0){
  20.         cnt=0;
  21.         for(auto &it:mp){
  22.             cnt+=(it.second*(it.second-1))/2;
  23.         }
  24.     }
  25.     cout<<cnt<<"\n";
  26. }
Success #stdin #stdout 0.01s 5320KB
comments (?)
stdin
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6 4
0 4 8 12 16 16
stdout
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5
https://ideone.com/RTTesU
language:
C++14 (gcc 8.3)
created:
5 days ago
visibility:
public

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