1 条题解
-
0
C++ :
#include<cstdio> #include<cmath> #include<set> #include<map> #include<algorithm> using namespace std; const double eps=1e-8; const int N=20010,M=50010; int n,m,q,cnt,i,x,y; map<int,int>T[20010]; inline int sgn(double x){ if(fabs(x)<eps)return 0; return x>0?1:-1; } struct P{ double x,y; P(){} P(double _x,double _y){x=_x,y=_y;} double operator*(const P&b){return x*b.y-y*b.x;} }a[N],b[N]; struct E{ int x,y;double o; E(){} E(int _x,int _y){x=_x,y=_y,o=atan2(a[y].x-a[x].x,a[y].y-a[x].y);} }e[M]; bool del[M],ex[M];int from[M],id[N],f[N]; struct EV{ double x;int y,t; EV(){} EV(double _x,int _y,int _t){x=_x,y=_y,t=_t;} }ev[M<<1]; inline bool cmpEV(const EV&a,const EV&b){ if(sgn(a.x-b.x))return a.x<b.x; return a.t<b.t; } namespace GetArea{ struct cmp{bool operator()(int a,int b){return e[a].o<e[b].o;}}; set<int,cmp>g[N];set<int,cmp>::iterator k;int i,j,q[M],t; void work(){ for(i=0;i<m+m;i++)if(!del[i]&&!ex[i]){ for(q[t=1]=j=i;;q[++t]=j=*k){ k=g[e[j].y].find(j^1);k++; if(k==g[e[j].y].end())k=g[e[j].y].begin(); if(*k==i)break; } double s=0; for(j=1;j<=t;j++)s+=a[e[q[j]].x]*a[e[q[j]].y],del[q[j]]=1; if(sgn(s)<0)continue; for(cnt++,j=1;j<=t;j++)from[q[j]]=cnt; } } } namespace ScanLine{ struct cmp{ bool operator()(int A,int B){ if(e[A].x==e[B].x)return e[A].o>e[B].o; double x=min(a[e[A].x].x,a[e[B].x].x), yA=(a[e[A].x].y-a[e[A].y].y)*(x-a[e[A].y].x)/(a[e[A].x].x-a[e[A].y].x)+a[e[A].y].y, yB=(a[e[B].x].y-a[e[B].y].y)*(x-a[e[B].y].x)/(a[e[B].x].x-a[e[B].y].x)+a[e[B].y].y; return yA>yB; } }; set<int,cmp>T; int cnt,i,j,k,g[M],v[M],nxt[M],ed,vis[N],t,tmp[N]; inline bool cmpC(int x,int y){return a[x].x<a[y].x;} inline void add(int x,int y){v[++ed]=y;nxt[ed]=g[x];g[x]=ed;} void dfs(int x){ vis[x]=1; if(a[x].y>a[t].y)t=x; for(int i=g[x];i;i=nxt[i])if(!vis[v[i]])dfs(v[i]); } inline double cal(int A,double x){ return(a[e[A].x].y-a[e[A].y].y)*(x-a[e[A].y].x)/(a[e[A].x].x-a[e[A].y].x)+a[e[A].y].y; } void connect(){ for(i=0;i<m+m;i++)add(e[i].x,e[i].y); for(i=1;i<=n;i++)if(!vis[i])dfs(t=i),ev[cnt++]=EV(a[t].x,t,2); for(i=0;i<m+m;i++)if(sgn(a[e[i].x].x-a[e[i].y].x)>0){ ev[cnt++]=EV(a[e[i].y].x,i,1); ev[cnt++]=EV(a[e[i].x].x,i,0); } sort(ev,ev+cnt,cmpEV); a[n+1]=P(10010,10010); a[n+2]=P(-10010,10010); e[m+m]=E(n+1,n+2); T.insert(m+m); e[m+m+1]=E(n+2,n+1); n+=2,m++; for(ed=0,i=1;i<=n;i++)g[i]=0; for(i=0;i<cnt;i++){ if(ev[i].t==0)T.erase(ev[i].y); if(ev[i].t==1)T.insert(ev[i].y); if(ev[i].t==2){ a[n+1]=P(ev[i].x,a[ev[i].y].y+eps); a[n+2]=P(ev[i].x-1,a[ev[i].y].y+eps); e[m+m]=E(n+1,n+2); T.insert(m+m); set<int,cmp>::iterator j=T.find(m+m); j--,add(*j,ev[i].y); T.erase(m+m); } } int newm=m+m; for(i=0;i<m+m;i++){ for(cnt=0,j=g[i];j;j=nxt[j]){ if(!sgn(a[v[j]].x-a[e[i].x].x)){ e[newm++]=E(v[j],e[i].x); e[newm++]=E(e[i].x,v[j]); continue; } if(!sgn(a[v[j]].x-a[e[i].y].x)){ e[newm++]=E(v[j],e[i].y); e[newm++]=E(e[i].y,v[j]); continue; } tmp[++cnt]=v[j]; } if(!cnt)continue; ex[i]=ex[i^1]=1; sort(tmp+1,tmp+cnt+1,cmpC); for(k=e[i].y,j=1;j<=cnt;k=n,j++){ a[++n]=P(a[tmp[j]].x,cal(i,a[tmp[j]].x)); e[newm++]=E(k,n); e[newm++]=E(n,k); e[newm++]=E(tmp[j],n); e[newm++]=E(n,tmp[j]); } e[newm++]=E(n,e[i].x); e[newm++]=E(e[i].x,n); } m=newm/2; } void location(){ for(i=cnt=0;i<m+m;i++)if(!ex[i]&&sgn(a[e[i].x].x-a[e[i].y].x)>0){ ev[cnt++]=EV(a[e[i].y].x,i,1); ev[cnt++]=EV(a[e[i].x].x,i,0); } for(i=0;i<q;i++)ev[cnt++]=EV(b[i].x,i,2); sort(ev,ev+cnt,cmpEV); T.clear(); for(i=0;i<cnt;i++){ if(ev[i].t==0)T.erase(ev[i].y); if(ev[i].t==1)T.insert(ev[i].y); if(ev[i].t==2){ a[n+1]=P(ev[i].x,b[ev[i].y].y); a[n+2]=P(ev[i].x-1,b[ev[i].y].y); e[m+m]=E(n+1,n+2); T.insert(m+m); set<int,cmp>::iterator j=T.find(m+m); if(j!=T.begin())j--,id[ev[i].y]=from[*j]; T.erase(m+m); } } } } inline int getid(){ int x,y; scanf("%d%d",&x,&y); if(T[x+10000][y])return T[x+10000][y]; T[x+10000][y]=++n; a[n]=P(x,y); return n; } bool g[610][610]; int main(){ scanf("%d%d",&q,&m); for(i=0;i<q;i++)scanf("%lf%lf",&b[i].x,&b[i].y); for(i=0;i<m;i++){ x=getid(); y=getid(); e[i<<1]=E(x,y); e[i<<1|1]=E(y,x); } ScanLine::connect(); for(i=0;i<m+m;i++)if(!ex[i])GetArea::g[e[i].x].insert(i); GetArea::work(); ScanLine::location(); for(i=0;i<q;i++)f[id[i]]=i+1; for(i=0;i<m+m;i++)if(!ex[i])g[f[from[i]]][f[from[i^1]]]=1; for(i=1;i<=q;i++){ for(x=g[i][i]=0,y=1;y<=q;y++)if(g[i][y])x++; printf("%d",x); for(y=1;y<=q;y++)if(g[i][y])printf(" %d",y); puts(""); } return 0; }
- 1
信息
- ID
- 1005
- 时间
- 1000ms
- 内存
- 128MiB
- 难度
- (无)
- 标签
- 递交数
- 0
- 已通过
- 0
- 上传者