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  1. #include<iostream>
  2. #include<cstdio>
  3. #include<cstring>
  4. #include<set>
  5. using namespace std;
  6.  
  7. struct self{int x,y;}s[40044];
  8. int m,a,b,c,z;
  9. set<double>q;
  10. bool zero=0;
  11.  
  12. bool ok(int x1,int y1,int x2,int y2)
  13. {
  14.     int x=x1-x2;
  15.     int y=y1-y2;
  16.     if(x==0)
  17.     {
  18.         if(!zero)
  19.         {
  20.             zero=1;
  21.             return true;
  22.         }
  23.         return false;
  24.     }
  25.     if(q.insert(double(y)/x).second)return true;
  26.     return false;
  27. }
  28.  
  29.  
  30. int main()
  31. {
  32.     scanf("%d",&m);
  33.     for(a=1;a<=m;a++)scanf("%d%d",&s[a].x,&s[a].y);
  34.  
  35.     for(a=1;a<=m;a++)
  36.         for(b=a+1;b<=m;b++)
  37.         if(ok(s[a].x,s[a].y,s[b].x,s[b].y))z++;
  38.  
  39.     cout<<z<<'\n';
  40.     return 0;
  41. }
Success #stdin #stdout 0s 3788KB
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https://ideone.com/R0MILm
language:
C++ (gcc 8.3)
created:
9 years ago
visibility:
secret

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