这是代码

#include<bits/stdc++.h>
using namespace std;
namespace IO{
    template<typename T>inline void read(T &x){
        x=0;bool w=1;char ch=getchar();
        while(!isdigit(ch)){ if(ch=='-')w=0; ch=getchar(); }
        while(isdigit(ch)) x=(x<<1)+(x<<3)+(ch^48),ch=getchar();
        x=(w==1?x:(~x+1));}
    template<typename T>inline void write(T x){
        if(x<0){putchar('-'),x=-x;}if(x==0){putchar('0');return ;}
        if(x>9)write(x/10);putchar(x%10+'0');return ;}
    template<typename T>inline void writesp(T &x){ write(x);putchar(32); }
    template<typename T>inline void writeln(T &x){ write(x);putchar(10); }
    #define For(i,j,k) for(int i=(j);i<=(k);++i)
}using namespace IO;

double dist(int x1,int y1,int x2,int y2)
{
    return (abs(x1-x2)*abs(x1-x2)+abs(y1-y2)*abs(y1-y2));
}

int X1,Y1,X2,Y2;

signed main()
{
    read(X1),read(Y1),read(X2),read(Y2);
    int N,ans1=0,ans2=0;read(N);For(i,1,N)
    {
        int x,y;
        read(x),read(y);
        double dist1=dist(x,y,X1,Y1);
        double dist2=dist(x,y,X2,Y2);
        bool p=((dist1<=dist2)?1:0);
        if(p)ans1=max(ans1,(int)ceil(dist1));
        else ans2=max(ans2,(int)ceil(dist2));
    }
    write(ans1+ans2);
    return 0;
}

我逛完 $WEB$ 后发现只有 $O(nlogn)$ 排序，但我想 $O(n)$ 貌似也可以，但斜挂了