如何做网站的源码,怎样制作微信小程序,除了网页外 网站还需要,花园桥网站建设板子题#xff0c;求多边形内核面积。 话说jls的板子返回的是边#xff0c;然后我就在冥思苦想怎么根据割边求面积啊。。 然后发现自己果然是个傻逼#xff0c;求一下交点存起来就好了。。。 //板子题到此为止了 1 #include iostream2 #include cstdio3 #in…板子题求多边形内核面积。 话说jls的板子返回的是边然后我就在冥思苦想怎么根据割边求面积啊。。 然后发现自己果然是个傻逼求一下交点存起来就好了。。。 //板子题到此为止了 1 #include iostream2 #include cstdio3 #include algorithm4 #include vector5 #include cmath6 #include deque7 8 using namespace std;9 typedef double db;10 const db eps1e-6;11 const db piacos(-1);12 int sign(db k){13 if (keps) return 1; else if (k-eps) return -1; return 0;14 }15 int cmp(db k1,db k2){return sign(k1-k2);}16 struct point{17 db x,y;18 point operator (const point k1) const{return (point){k1.xx,k1.yy};}19 point operator - (const point k1) const{return (point){x-k1.x,y-k1.y};}20 point operator * (db k1) const{return (point){x*k1,y*k1};}21 point operator / (db k1) const{return (point){x/k1,y/k1};}22 db getP()const { return sign(y)1||(sign(y)0sign(x)-1);}23 };24 db cross(point k1,point k2){ return k1.x*k2.y-k1.y*k2.x;}25 db dot(point k1,point k2){ return k1.x*k2.xk1.y*k2.y;}26 db rad(point k1,point k2){ return atan2(cross(k1,k2),dot(k1,k2));}27 int compareangle(point k1,point k2){28 return k1.getP()k2.getP()||(k1.getP()k2.getP()sign(cross(k1,k2))0);29 }30 point getLL(point k1,point k2,point k3,point k4){31 db w1cross(k1-k3,k4-k3),w2cross(k4-k3,k2-k3);32 return (k1*w2k2*w1)/(w1w2);33 }34 struct line{35 point p[2];36 line(point k1,point k2){p[0]k1;p[1]k2;}37 point operator[](int k){ return p[k];}38 int include(point k){ return sign(cross(p[1]-p[0],k-p[0])0);}39 point dir(){ return p[1]-p[0];}40 };41 point getLL(line k1,line k2){42 return getLL(k1[0],k1[1],k2[0],k2[1]);43 }44 int parallel(line k1,line k2){ return sign(cross(k1.dir(),k2.dir()))0;}45 int sameDir(line k1,line k2){46 return parallel(k1,k2)sign(dot(k1.dir(),k2.dir()))1;47 }48 int operator (line k1,line k2){49 if(sameDir(k1,k2))return k2.include(k1[0]);50 return compareangle(k1.dir(),k2.dir());51 }52 int checkpos(line k1,line k2,line k3){ return k3.include(getLL(k1,k2));}53 vectorline getHL(vectorline L){54 sort(L.begin(),L.end());dequeline q;55 for(int i0;iL.size();i){56 if(isameDir(L[i],L[i-1]))continue;57 while (q.size()1!checkpos(q[q.size()-2],q[q.size()-1],L[i]))q.pop_back();58 while (q.size()1!checkpos(q[1],q[0],L[i]))q.pop_front();59 q.push_back(L[i]);60 }61 while (q.size()2!checkpos(q[q.size()-2],q[q.size()-1],q[0]))q.pop_back();62 while (q.size()2!checkpos(q[1],q[0],q[q.size()-1]))q.pop_front();63 vectorline ans;for(int i0;iq.size();i)ans.push_back(q[i]);64 return ans;65 }66 int t,n;67 point p[1551];68 bool cw(){//时针69 db s0;70 for(int i1;in-1;i){71 scross(p[i]-p[0],p[i1]-p[0]);72 }73 return s0;74 }75 vectorlinel;76 int main(){77 scanf(%d,t);78 while (t--){79 scanf(%d,n);80 for(int i0;in;i){81 scanf(%lf%lf,p[i].x,p[i].y);82 }83 if(!cw())reverse(p,pn);84 for(int i0;in;i){85 l.push_back(line(p[i],p[(i1)%n]));86 }87 lgetHL(l);88 if(l.size()3){89 printf(0.00\n);90 } else{91 vectorpoint a;92 for(int i0;il.size();i){93 a.push_back(getLL(l[i],l[(i1)%l.size()]));94 }95 db ans 0;96 for(int i1;ia.size()-1;i)97 anscross(a[i]-a[0],a[i1]-a[0]);98 ans/2;99 printf(%.2f\n,ans);
100 }
101 l.clear();
102 }
103 } View Code 转载于:https://www.cnblogs.com/MXang/p/10453657.html
