WA#9求助

// luogu-judger-enable-o2
#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

const double eps=1e-8;
const int N=500010;

inline int dcmp(double x) {
    if (fabs(x)<=eps) {
        return 0;
    }
    return x<0?-1:1;
}

struct point {
    double x;
    double y;
    point(){}
    point(double u,double v) {
        x=u;
        y=v;
    }
    bool operator < (const point &rhs) const {
        return dcmp(x-rhs.x)<0||(dcmp(x-rhs.x)==0&&dcmp(y-rhs.y)<0);
    }
};

point operator + (point A,point B) {
    return point(A.x+B.x,A.y+B.y);
}

point operator - (point A,point B) {
    return point(A.x-B.x,A.y-B.y);
}

point operator * (point A,double p) {
    return point(A.x*p,A.y*p);
}

point operator * (double p,point A) {
    return point(A.x*p,A.y*p);
}

double operator * (point A,point B) {
    return (A.x*B.y)-(A.y*B.x);
}

point operator ^ (point A,point B) {
    return point(A.x*B.x,A.y*B.y);
}

inline double dis(point A,point B) {
    return sqrt((A.x-B.x)*(A.x-B.x)+(A.y-B.y)*(A.y-B.y));
}

bool operator == (point A,point B) {
    return dcmp(A.x-B.x)==0&&dcmp(A.y-B.y)==0;
}

point p[N];
int n;
point sta[N];
int top;
double ans;
bool same_x=1,same_y=1;

inline bool cmpx(point A,point B) {
    return A.y<=B.y;
}

inline bool cmpy(point A,point B) {
    return A.x<=B.x;
}

inline void init() {
    for(int i=0;i<n;i++) {
        scanf("%lf%lf",&p[i].x,&p[i].y);
    }
    for(int i=1;i<n;i++) {
        if (dcmp(p[i+1].x-p[i].x)!=0) {
            same_x=0;
        }
        if (dcmp(p[i+1].y-p[i].y)!=0) {
            same_y=0;
        }
    }
    if (same_x) {
        sort(p,p+n,cmpx);
        ans=p[n-1].y-p[0].y;
        return;
    }
    if (same_y) {
        sort(p,p+n,cmpy);
        ans=p[n-1].x-p[0].x;
        return;
    }
    sort(p,p+n);
    n=unique(p,p+n)-p;
}

inline int Graham() {
    top=0;
    for(int i=0;i<n;i++) {
        while(top>1&&(sta[top-1]-sta[top-2])*(p[i]-sta[top-2])<0) {
            top--;
        }
        sta[top++]=p[i];
    }
    int k=top;
    for(int i=n-2;i>=0;i--) {
        while(top>k&&(sta[top-1]-sta[top-2])*(p[i]-sta[top-2])<0) {
            top--;
        }
        sta[top++]=p[i];
    }
    if (n>1) {
        top--;
    }
    return top;
}

inline double get_diameter() {
    double d=0;
    if (top==2) {
        return dis(sta[0],sta[1]);
    }
    sta[++top]=sta[0];
    int j=2;
    for(int i=0;i<top;i++) {
        while((sta[i+1]-sta[i])*(sta[j]-sta[i])<(sta[i+1]-sta[i])*(sta[j+1]-sta[i])) {
            j=(j+1)%top;
        }
        d=max(d,max(dis(sta[i],sta[j]),dis(sta[i+1],sta[j])));
    }
    return d;
}

int main() {
    scanf("%d",&n);
    init();
    int s=Graham();
    if (same_x||same_y) {
        printf("%.0lf\n",ans*ans);
        return 0;
    }
    ans=get_diameter();
    printf("%.0lf\n",ans*ans);
    return 0;
}