计算几何的题目，很简单；
自己随手敲了个，纪念下！
1 #include<cstdio> 2 #include<cmath> 3 using namespace std; 4 5 struct point 6 { 7 double x,y; 8 point(double x=0,double y=0):x(x),y(y) { } 9 } a,b,c,d; 10 11 point midd(point a,point b) 12 { 13 return point((a.x+b.x)/2.0,(a.y+b.y)/2.0); 14 } 15 point operator + (point a,point b) 16 { 17 return point(a.x+b.x,a.y+b.y); 18 } 19 point operator - (point a,point b) 20 { 21 return point(a.x-b.x,a.y-b.y); 22 } 23 point operator * (point a,double p) 24 { 25 return point(a.x*p,a.y*p); 26 } 27 point operator / (point b,double p) 28 { 29 return point(a.x/p,a.y/p); 30 } 31 double cross(point a,point b) 32 { 33 return a.x*b.y-b.x*a.y; 34 } 35 point getlineintersection(point p,point v,point q,point w) 36 { 37 point u=p-q; 38 double t=cross(w,u)/cross(v,w); 39 return p+v*t; 40 } 41 double area(point a,point b,point c) 42 { 43 return cross(b-a,c-a)/2.0; 44 } 45 double dis(point a,point b) 46 { 47 return sqrt((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y)); 48 } 49 double line(point a,point b,point c,point d) 50 { 51 return dis(a,b)+dis(b,c)+dis(c,d)+dis(d,a); 52 } 53 54 55 int main() 56 { 57 int t,ca; 58 scanf("%d",&t); 59 while(t--) 60 { 61 scanf("%d",&ca); 62 printf("%d ",ca); 63 a.x=0.0,a.y=0.0,b.y=0.0; 64 scanf("%lf%lf%lf%lf%lf",&b.x,&c.x,&c.y,&d.x,&d.y); 65 point dd=midd(a,b); 66 point aa=midd(b,c); 67 point cc=midd(a,d); 68 point bb=midd(c,d); 69 point aaa=getlineintersection(d,d-dd,a,a-aa); 70 point bbb=getlineintersection(a,aa-a,b,bb-b); 71 point ccc=getlineintersection(c,cc-c,b,bb-b); 72 point ddd=getlineintersection(c,cc-c,d,dd-d); 73 printf("%.3lf ",area(a,b,bbb)/160.0); 74 printf("%.3lf ",area(b,c,ccc)/160.0); 75 printf("%.3lf ",area(c,d,ddd)/160.0); 76 printf("%.3lf ",area(d,a,aaa)/160.0); 77 printf("%.3lf ",((area(ddd,aaa,bbb)+area(bbb,ccc,ddd))/160.0)); 78 printf("%.0lf ",ceil(line(aaa,bbb,ccc,ddd)*16.5)); 79 } 80 return 0; 81 }