https://github.com/lychees/ACM-Training/tree/master/Weekly/2019/09.30

A.cpp

// https://paste.ubuntu.com/p/g7hk9rjTkc
#include<bits/stdc++.h>
#define mset(a,b) memset(a,b,sizeof(a))
using namespace std;
const int N=2e3+50;
long long  xx[N],yy[N];
//long long  qx[N],qy[N];
long long  res[N];
struct Point //向量,但是主要判断方向与自己平行的多少个
{
    long long  x,y;
    Point() {}
    Point(long long  x,long long  y):x(x),y(y) {}
    Point operator -(const Point & o)
    {
        return Point(x-o.x,y-o.y);
    }
    Point to()const//
    {
        if(x<0||(x==0&& y < 0 )) return Point(-x,-y);
        return Point(x,y);
    }
    long long  operator ^(const Point &o)
    {
        return x*o.y-y*o.x;
    }
    bool operator < ( const Point& o) const//极角排序
    {
        return (to()^o.to())>0;
    }
} q[N],a[N];
map<Point,long long > mmp;
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    long long  n,m;
    while(cin>>n>>m)
    {
        for(long long  i=1; i<=n; ++i)
            cin>>a[i].x>>a[i].y;
        for(long long  i=1; i<=m; ++i)
        {
            mmp.clear();
            res[i]=0;
            cin>>q[i].x>>q[i].y;
            for(long long  j=1; j<=n; ++j)
            {
                Point p=q[i]-a[j];
                mmp[p]++;
            }
            for(long long  j=1; j<=n; ++j)
            {

                Point p=q[i]-a[j];
                p=Point(-p.y,p.x);
                res[i]+=mmp.count(p)?mmp[p]:0;
            }
            res[i]/=2;
        }
        for(long long  i=1; i<=n; ++i) //对于第i个点垂点
        {
            mmp.clear();
            for(long long  j=1; j<=n; ++j)
                if(i!=j)
                    mmp[Point(a[i]-a[j])]++;
            for(long long  j=1; j<=m; ++j)
            {
                Point p=q[j]-a[i];
                p=Point(-p.y,p.x);
                res[j]+=mmp.count(p)?mmp[p]:0;
            }
        }
        for(long long  i=1; i<=m; ++i)
            cout<<res[i]<<endl;

    }
    return 0;
}