bzoj1822

显然是二分+最大流判定
但比较烦的是判断线段和圆及其内部是否有公共点
我的判断方法是错的，但是数据弱
目前只知道推公式分类讨论，如果有简单的方法求教

 const inf=;
 type node=record
        flow,po,next:longint;
      end;
      point=record
        x,y:longint;
      end;

 var e:array[..] of node;
     a,b,c:array[..] of point;
     can:array[..,..] of boolean;
     g,cur,v,w,pre,p,numh,h:array[..] of longint;
     q,l,r,t,ans,mid,i,j,n,m,k,len:longint;
     ff,ch:boolean;

 function dis(a,b:point):double;
   begin
     exit(sqrt(sqr(a.x-b.x)+sqr(a.y-b.y)));
   end;

 function cross(a,b,c:point):double;
   begin
     cross:=abs((a.x-b.x)*(a.y-c.y)-(a.x-c.x)*(a.y-b.y));
     cross:=cross/dis(a,b);
   end;

 procedure add(x,y,f:longint);
   begin
     inc(len);
     e[len].po:=y;
     e[len].flow:=f;
     e[len].next:=p[x];
     p[x]:=len;
   end;

 function sap:longint;
   var u,i,j,tmp,q:longint;
   begin
     fillchar(h,sizeof(h),);
     fillchar(numh,sizeof(numh),);
     for i:= to t do
       cur[i]:=p[i];
     u:=;
     sap:=;
     numh[]:=t+;
     while h[]<t+ do
     begin
       i:=cur[u];
       while i<>- do
       begin
         j:=e[i].po;
         if (e[i].flow>) and (h[u]=h[j]+) then
         begin
           pre[j]:=u;
           cur[u]:=i;
           u:=j;
           if u=t then
           begin
             inc(sap);
             if sap=m then exit;
             while u<> do
             begin
               u:=pre[u];
               j:=cur[u];
               dec(e[j].flow);
               inc(e[j xor ].flow);
             end;
           end;
           break;
         end;
         i:=e[i].next;
       end;
       if i=- then
       begin
         dec(numh[h[u]]);
         if numh[h[u]]= then exit;
         tmp:=t;
         q:=-;
         i:=p[u];
         while i<>- do
         begin
           j:=e[i].po;
           if e[i].flow> then
             if h[j]<tmp then
             begin
               q:=i;
               tmp:=h[j];
             end;
           i:=e[i].next;
         end;
         h[u]:=tmp+;
         inc(numh[h[u]]);
         cur[u]:=q;
         if u<> then u:=pre[u];
       end;
     end;
   end;

 function check(s:longint):boolean;
   var q,i,j:longint;
   begin
     fillchar(p,sizeof(p),);
     len:=-;
     q:=;
     for i:= to n do
     begin
       add(,i,s div w[i]+);
       add(i,,);
       if s div w[i]*w[i]>q then q:=s div w[i]*w[i];
     end;
     for i:= to m do
     begin
       add(i+n,t,);
       add(t,i+n,);
       for j:= to n do
         if can[i,j] then
         begin
           add(j,i+n,);
           add(i+n,j,);
         end;
     end;
     if sap=m then
     begin
       ans:=q;
       exit(true);
     end
     else exit(false);
   end;

 begin
   readln(n,m,k);
   for i:= to n do
   begin
     readln(a[i].x,a[i].y,v[i],w[i]);
     if w[i]>r then r:=w[i];
   end;
   for i:= to m do
     readln(b[i].x,b[i].y);
   for i:= to k do
     readln(c[i].x,c[i].y,g[i]);
   for i:= to m do
   begin
     ch:=false;
     for j:= to n do
       if dis(b[i],a[j])<=v[j] then
       begin
         ff:=true;
         for q:= to k do
           if cross(b[i],a[j],c[q])<g[q] then
           begin
             ff:=false;
             break;
           end;
         if ff then
         begin
           can[i,j]:=true;
           ch:=true;
         end;
       end;

     if not ch then
     begin
       writeln(-);
       halt;
     end;
   end;
   t:=n+m+;
   l:=;
   r:=r*m;
   while l<=r do
   begin
     mid:=(l+r) shr ;
     if check(mid) then r:=ans- else l:=mid+;
   end;
   writeln(ans);
 end.