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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3.  
  4. int main() {
  5.     int n, k;
  6.     cin >> n >> k;
  7.  
  8.     vector<int> a(n);
  9.  
  10.     for(int i = 0; i < n; i++) {
  11.         cin >> a[i];
  12.     }
  13.  
  14.  
  15.  
  16.    unordered_map<int,int>mp;
  17.    int cnt = 0;
  18.  
  19.   for(int i = 0 ; i < n ;i++){
  20.  
  21.   	int cur = a[i] - k;
  22.   	int cur1 = k + a[i];
  23.  
  24.   	if(mp.find(cur) != mp.end()){
  25.   		cnt += mp[cur];
  26.   	}
  27.  
  28.   	if(k != 0 && mp.find(cur1) != mp.end()){
  29.   		cnt += mp[cur1];
  30.   	}
  31.   	mp[a[i]]++;
  32.   }
  33.    cout<<cnt;
  34.     return 0;
  35. }
Success #stdin #stdout 0s 5316KB
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stdin
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5 2
1 5 3 4 2
stdout
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3
https://ideone.com/UAHGB1
language:
C++ (gcc 8.3)
created:
1 day ago
visibility:
public

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