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  1. #include<bits/stdc++.h>
  2. using namespace std; 
  3.  
  4.  
  5. int main(){
  6.     int n,k; cin>>n>>k;
  7.     if(k<0){
  8.     	cout<<-1;
  9.     }
  10.     vector<int>arr(n);
  11.     for(int i = 0 ; i< n ; i++){
  12.     		cin>>arr[i];
  13.     }
  14.     unordered_map<int,int>hash;
  15.     int k_halfcount  = 0 ; int smaller = 0 ; 
  16.     for(int i = 0 ; i<n;i++){
  17.     	if(arr[i]==k/2 || arr[i]==-k/2){
  18.     	    k_halfcount++;
  19.     	}
  20.     	else if((abs(arr[i])<k/2)){
  21.     		smaller++;
  22.     	}
  23.     }
  24.     cout<<(k_halfcount)*(k_halfcount-1)/2 + k_halfcount*smaller;
  25.  
  26.  
  27. 	return 0 ; 
  28. }
Success #stdin #stdout 0.01s 5284KB
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https://ideone.com/A7y45R
language:
C++ (gcc 8.3)
created:
2 days ago
visibility:
public

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