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  1. #include <bits/stdc++.h> 
  2.  
  3. using namespace std;
  4.  
  5. int main() 
  6. { 
  7. long long int a;
  8. cin>>a;
  9. long long int b;cin>>b;
  10.  
  11. map<long long int,long long int>mp;
  12. long long int arr[a];
  13. for(int i=0;i<a;i++)
  14. {
  15. int ele; cin>>ele;
  16. arr[i]=ele;
  17. mp[ele]++;
  18. }
  19.    long long int dif=0;int cnt=0;
  20. for(int i=0;i<a;i++)
  21. {
  22. dif=b-arr[i];
  23. if(dif==0){mp[arr[i]]--;cnt++;}
  24.  
  25. else if(mp[dif]>0)
  26. {
  27. cnt++;
  28.  mp[dif]-=1;
  29. mp[arr[i]]--;
  30. }
  31. else dif=0;
  32. }
  33.  cout<<cnt<<endl ;
  34. }
Success #stdin #stdout 0s 4308KB
comments (?)
stdin
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7 5
1 1 3 4 5 7 7
stdout
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3
https://ideone.com/VmMSWG
language:
C++14 (clang 8.0)
created:
4 years ago
visibility:
public

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