计算几何模板（未调试，更新中）

计算几何学习中，一边应用一边订正与更新模板

干脆写了一个double的和一个long long(避免实数运算)的

 double

#include<cmath>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;

const double eps=1e-7;

struct point{
    double x,y;
    point(){}
    point (double a,double b): x(a),y(b) {}
    
    friend point operator + (const point &a,const point &b){
        return point(a.x+b.x,a.y+b.y);
    }
    
    friend point operator - (const point &a,const point &b){
        return point(a.x-b.x,a.y-b.y);
    }
    
    friend point operator * (const double &r,const point &a){
        return point(r*a.x,r*a.y);
    }
    
    friend bool operator == (const point &a,const point &b){
        return (abs(a.x-b.x)<eps && abs(a.y-b.y)<eps);
    }
    
    double norm(){
        return sqrt(x*x+y*y);
    }      
};

inline double det(point a,point b) {return a.x*b.y-a.y*b.x;}
inline double dot(point a,point b) {return a.x*b.x+a.y*b.y;}
inline double dist(point a,point b) {return (a-b).norm();}
inline point rotate(point p,double A) 
{
    return point(p.x*cos(A)-p.y*sin(A),p.x*sin(A)+p.y*cos(A));
}

inline bool line_cross_segment(point s,point t,point a,point b)
{
    return !(det(s-a,t-a)*det(s-b,t-b)>eps);
}

inline bool seg_cross_seg(point a,point b,point c,point d)
{
    if (min(c.x,d.x)>max(a.x,b.x) || min(a.x,b.x)>max(c.x,d.x) || min(c.y,d.y)>max(a.y,b.y) || min(a.y,b.y)>max(c.y,d.y))
        return false;
    return det(a-c,d-c)*det(b-c,d-c)<eps && det(c-a,b-a)*det(d-a,b-a)<eps;
}

inline double p_line_dist(point p,point s,point t) {return det(s-p,t-p)/dist(s,t);}

inline point Pro(point p,point s,point t)  //垂足 
{
    double r=dot(t-s,p-s)/dot(t-s,t-s);
    return s+r*(t-s);
}

inline bool On (point p,point s,point t){                 //点在线段上 
    return (abs(det(p-s,t-s))<eps && dot(p-s,p-t)<eps);
}

inline double p_segment_dist(point p,point s,point t) 
{
    if (On(Pro(p,s,t),s,t)) return p_line_dist(p,s,t);
        else return min(dist(p,s),dist(p,t));
}

inline bool parallel(point a,point b,point c,point d){return abs(det(a-b,c-d))<eps;}

inline point line_make_point(point s1,point t1,point s2,point t2) //逻辑上必须先判断parallel
{
    double a1=det(s1-s2,t2-s2);
    double a2=det(t1-s2,t2-s2);
    return 1/(a1-a2)*(a1*t1-a2*s1);
}

long long

#include<cmath>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;

struct point{
    long long x,y;
    point(){}
    point (long long a,long long b): x(a),y(b) {}
    
    friend point operator + (const point &a,const point &b){
        return point(a.x+b.x,a.y+b.y);
    }
    
    friend point operator - (const point &a,const point &b){
        return point(a.x-b.x,a.y-b.y);
    }
    
    friend point operator * (const long long &r,const point &a){
        return point(r*a.x,r*a.y);
    }
    
    friend bool operator == (const point &a,const point &b){
        return a.x==b.x && a.y==b.y;
    }
    
    long long sqrnorm(){
        return x*x+y*y;
    }      
};

inline long long det(point a,point b) {return a.x*b.y-a.y*b.x;}
inline long long dot(point a,point b) {return a.x*b.x+a.y*b.y;}
inline long long sqrdist(point a,point b) {return (a-b).sqrnorm();}

inline bool line_cross_segment(point s,point t,point a,point b)
{
    return det(s-a,t-a)*det(s-b,t-b)<=0;
}

inline bool seg_cross_seg(point a,point b,point c,point d)
{
    if (min(c.x,d.x)>max(a.x,b.x) || min(a.x,b.x)>max(c.x,d.x) || min(c.y,d.y)>max(a.y,b.y) || min(a.y,b.y)>max(c.y,d.y))
        return false;
    return det(a-c,d-c)*det(b-c,d-c)<=0 && det(c-a,b-a)*det(d-a,b-a)<=0;
}

inline bool On (point p,point s,point t){                 //点在线段上 
    return det(p-s,t-s)==0 && dot(p-s,p-t)<=0;
}

inline bool parallel(point a,point b,point c,point d){return det(a-b,c-d)==0;}