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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3.  
  4. int ans(vector<int> &v,int &k){
  5. 	unordered_map<int,int>m;
  6. 	int count=0;
  7. 	for(int i=0;i<v.size();i++){
  8. 		int c= k+v[i];
  9. 		if(m[c]>0)count+=m[c];
  10.  
  11. 		m[v[i]]++;
  12. 	}
  13. 	return count;
  14. }
  15. int main() {
  16. 	// your code goes here
  17. 	int n;cin>>n;
  18. 	vector<int>v(n);
  19. 	for(int i=0;i<n;i++)cin>>v[i];
  20. 	int k;cin>>k;
  21. 	cout<<ans(v,k)<<endl;
  22. 	return 0;
  23. }
Success #stdin #stdout 0.01s 5320KB
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https://ideone.com/937YBk
language:
C++14 (gcc 8.3)
created:
6 hours ago
visibility:
public

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