計算幾何 圓 二維模板

#include#include#include#include#include#define fir first

#define sec second
using namespace std;
const double eps = 1e-8;
const double pi = acos(-1.0);
int dcmp(double x)
//兩圓求公切線
//a[i] 為第i條切線與圓a的交點
int get_tangents(circle a, circle b, pnode *a, pnode *b)
double d = sqrt((a.x - b.x) * (a.x - b.x) + (a.y - b.y) * (a.y - b.y)); //圓心距
double rdiff = a.r - b.r; //兩圓半徑差
double rsum = a.r + b.r; //兩圓半徑和
if(dcmp(d - rdiff) < 0)
return 0; //1.內含
double base = atan2(b.y - a.y, b.x - a.x); //向量ab的極角
if(dcmp(d) == 0) return -1; //2.重合
if(dcmp(d - rdiff) == 0)
double ang = acos((a.r - b.r) / d);
a[cnt] = a.point(base + ang); b[cnt] = b.point(base + ang); cnt++; //4.相交（外切、外離的外公切線也在此求出）
a[cnt] = a.point(base - ang); b[cnt] = b.point(base - ang); cnt++; //兩條外公切線的切點
if(dcmp(d - rsum) == 0)
else if(dcmp(d - rsum) > 0)
return cnt;
}int main()

二維計算幾何模板 圓

include include include include include include include include include include include include define eps 1e 6 log x define e exp 1.0 define mod 1000...

計算幾何 二維幾何 模板

幾何意義 向量的點積 a b a b a b cos cos 若cos cos 為正，兩向量之間的夾角為銳角 為負，兩向量夾角為鈍角 為量，兩向量夾角為直角。b在a方向上的投影 向量的叉積 a b a b a b sin sin 數值上表示a和b構成的平行四邊形的面積。include using n...

二維計算幾何模板（點，線）

include include include include include include include include include include include define e exp 1.0 define mod 1000000007 define inf 0x7fffffff d...