判断圆和矩形是否相交

#include <iostream>
#include
#include <cstdio>
#include <cstring>
#include <cmath>
using namespace std;
 
const double eps = 1e-8;
const double pi = acos(-1);
 
struct POINT
{
    double x, y;
    POINT(double a, double b){
        x = a;
        y = b;
    }
    POINT() {}
};
 
struct Seg
{
    POINT a, b;
    Seg() {}
    Seg(POINT x, POINT y){
        a = x;
        b =y;
    }
};
 
struct Line
{
    POINT a, b;
    Line() {}
    Line(POINT x, POINT y){
        a = x;
        b = y;
    }
};
 
struct Cir
{
    POINT o;
    double r;
    Cir() {}
    Cir(POINT oo, double rr){
        o = oo;
        r = rr;
    }
};
 
struct Rec
{
    POINT p1, p2, p3, p4;
    Rec() { }
    Rec(POINT a, POINT b, POINT c, POINT d){
        p1 = a;
        p2 = b;
        p3 = c;
        p4 = d;
    }
};
 
int dcmp(double x)
{
    if(fabs(x) < eps) return 0;
    else return x < 0 ? -1 : 1;
}
 
double x, y, r;
double x1, yy1, x2, y2;
 
double cross(POINT o, POINT a, POINT b)
{
    return (a.x - o.x) * (b.y - o.y) - (b.x - o.x) * (a.y - o.y);
}
 
double dis(POINT a, POINT b)
{
    return sqrt((a.x - b.x) * (a.x - b.x) + (a.y - b.y) * (a.y - b.y));
}
 
double PointToLine(POINT p, Line l)
{
    return fabs(cross(p, l.a, l.b)) / dis(l.a, l.b);
}
 
double PointToSeg(POINT p, Seg s)
{
    POINT tmp = p;
    tmp.x += s.a.y - s.b.y;
    tmp.y += s.b.x - s.a.x;
    if(cross(s.a, p, tmp) * cross(s.b, p, tmp) >= eps){
        return min(dis(p, s.a), dis(p, s.b));
    }
    return PointToLine(p, Line(s.a, s.b));
}
 
//
bool Circle_Rectangle_cross(Cir O, Rec R)
{
    if(dcmp(dis(O.o, R.p1) - O.r) < 0 && dcmp(dis(O.o, R.p2) - O.r) < 0 && dcmp(dis(O.o, R.p3) - O.r) < 0 && dcmp(dis(O.o, R.p4) - O.r) < 0)
        return false;
    if(dcmp(PointToSeg(O.o, Seg(R.p1, R.p2)) - O.r) <= 0) return true;
    if(dcmp(PointToSeg(O.o, Seg(R.p2, R.p3)) - O.r) <= 0) return true;
    if(dcmp(PointToSeg(O.o, Seg(R.p3, R.p4)) - O.r) <= 0) return true;
    if(dcmp(PointToSeg(O.o, Seg(R.p4, R.p1)) - O.r) <= 0) return true;
    return false;
}
 
int main()
{
//    freopen("1.txt", "r", stdin);
//    freopen("2.txt", "w", stdout);
    int T;
    scanf("%d", &T);
    while(T -- ){
        Cir O;
        Rec R;
        scanf("%lf %lf %lf", &O.o.x, &O.o.y, &O.r);
        scanf("%lf %lf %lf %lf", &R.p1.x, &R.p1.y, &R.p2.x, &R.p2.y);
        scanf("%lf %lf %lf %lf", &R.p3.x, &R.p3.y, &R.p4.x, &R.p4.y);
        if(Circle_Rectangle_cross(O, R)) puts("Yes!");
        else puts("No!");
    }
    return 0;
}
原文地址:https://www.cnblogs.com/zhoug2020/p/5061564.html