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  1. #include <bits/stdc++.h>
  2.  
  3. using namespace std;
  4.  
  5. int n;
  6. int a[1000001];
  7. int b[1000001];
  8.  
  9. void sub1()
  10. {
  11.       int dem=0;
  12.       for(int i=1; i<=n-1; i++)
  13.        for(int j=i+1; j<=n; j++)
  14.       if (a[i]==a[j] && b[i]!=b[j]) dem++;
  15.       cout << dem;
  16. }
  17.  
  18. map < int, map <int,int> > M;
  19. void sub2()
  20. {
  21.       for(int i=1; i<=n; i++)
  22.       M[a[i]][b[i]]++;
  23.  
  24.       int kq=0;
  25.       for(map < int, map <int,int> > :: iterator it=M.begin(); it!=M.end(); it++)
  26.       {
  27.             int sl=M[it->first].size();
  28.             for(map <int,int> :: iterator itb=M[it->first].begin();
  29.             itb!=M[it->first].end(); itb++)
  30.             {
  31.                   int sltrung=M[it->first][itb->first];
  32.                   kq=kq-sltrung*(sltrung-1)/2;
  33.                   sl=sl+sltrung-1;
  34.             }
  35.             kq=kq+sl*(sl-1)/2;
  36.       }
  37.  
  38.       cout << kq;
  39. }
  40.  
  41. int main()
  42. {
  43.       ios_base::sync_with_stdio(false);
  44.       cin.tie(0);
  45.       freopen("CAU1.INP", "r", stdin);
  46.       freopen("CAU1.OUT", "w", stdout);
  47.       cin >> n;
  48.       for(int i=1; i<=n; i++) cin >> a[i] >> b[i];
  49.       if (n<1000) sub1();
  50.       else sub2();
  51.       return 0;
  52. }
Success #stdin #stdout 0.01s 5288KB
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https://ideone.com/tCq7F3
language:
C++14 (gcc 8.3)
created:
16 hours ago
visibility:
public

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