BZOJ2961: 共点圆

好久没发了

CDQ分治，具体做法见XHR的论文…

 /**************************************************************
     Problem: 2961
     User: zhuohan123
     Language: C++
     Result: Accepted
     Time:5060 ms
     Memory:41704 kb
 ****************************************************************/

 #include <iostream>
 #include <cmath>
 #include <cstdio>
 #include <cstring>
 #include <algorithm>
 using namespace std;
 const double eps=1e-,inf=1e12;
 struct point
 {
     double x,y;
     point(){x=y=;}
     point(double X,double Y){x=X,y=Y;}
     friend bool operator<(point a,point b)
     {
         if(abs(a.x-b.x)<eps)return a.y+eps<b.y;
         else return a.x+eps<b.x;
     }
 };
 inline point V(point s,point e){return point(e.x-s.x,e.y-s.y);}
 inline double crossP(point a,point b){return a.x*b.y-b.x*a.y;}
 inline double dotP(point a,point b){return a.x*b.x+a.y*b.y;}
 struct T{int ispo;point o;}q[];
 point t[];int tnum;
 point up[];int unum;
 point dw[];int dnum;
 bool ans[];
 void imerge(int l,int r)
 {
     if(l==r)return ;
     int mid=(l+r)/;
     imerge(l,mid);imerge(mid+,r);
     tnum=;
     for(int i=l;i<=mid;i++)
         if(!q[i].ispo)t[++tnum]=q[i].o;
     sort(t+,t+tnum+);
     unum=;
     for(int i=;i<=tnum;i++)
     {
         while(unum>&&crossP(V(up[unum-],up[unum]),V(up[unum],t[i]))>-eps)unum--;
         up[++unum]=t[i];
     }
     up[unum+].x=up[unum].x+eps;up[unum+].y=-inf;
     dnum=;
     for(int i=tnum;i;i--)
     {
         while(dnum>&&crossP(V(dw[dnum-],dw[dnum]),V(dw[dnum],t[i]))>-eps)dnum--;
         dw[++dnum]=t[i];
     }
     dw[dnum+].x=dw[dnum].x-eps;dw[dnum+].y=inf;
     if(tnum!=)
     for(int i=mid+;i<=r;i++)
         if(q[i].ispo&&ans[i])
         {
             point near;
             if(q[i].o.y<)
             {
                 int L=,R=unum;
                 while(L<=R)
                 {
                     int Mid=(L+R)/;
                     if(dotP(q[i].o,V(up[Mid],up[Mid+]))>-eps)near=up[Mid],R=Mid-;
                     else L=Mid+;
                 }
             }
             else
             {
                 int L=,R=dnum;
                 while(L<=R)
                 {
                     int Mid=(L+R)/;
                     if(dotP(q[i].o,V(dw[Mid+],dw[Mid]))<eps)near=dw[Mid],R=Mid-;
                     else L=Mid+;
                 }
             }
             if(*near.x*q[i].o.x+*near.y*q[i].o.y-q[i].o.x*q[i].o.x-q[i].o.y*q[i].o.y<eps)ans[i]=false;
         }
 }
 int main(int argc, char *argv[])
 {
     //freopen("1.in","r",stdin);
     //freopen("1.out","w",stdout);
     int n;scanf("%d",&n);
     for(int i=;i<=n;i++)
     {
         scanf("%d%lf%lf",&q[i].ispo,&q[i].o.x,&q[i].o.y);
         if(q[i].ispo)ans[i]=true;
     }
     for(int i=;i<=n&&q[i].ispo;i++)ans[i]=false;
     imerge(,n);
     for(int i=;i<=n;i++)
         if(q[i].ispo)puts(ans[i]?"Yes":"No");
     return ;
 }