POJ 3575(计算几何与二分-无尽的小数处理)

这题 写了将近半个月……总是在D各种Bug

总的说来-这题最难应该是在精度处理上

1

1

0 0 1

这组数据过了就说明精度处理差不多了……

Program kingdom;
const
   maxn=100;
   maxm=100;
   le=0.000000001;
type
   circle=record
            x,y,r:double;
          end;
var
   s:array[1..maxn,1..1000] of circle;
   n,i,j,k:longint;
   m:array[1..maxn] of longint;
   ans:array[1..maxn,1..4] of double;
   wanted:array[1..maxn] of double;
   b:array[1..maxn] of boolean;
   l,r:double;
function arccos(cosa:double):double;
var
   sina,tana:double;
begin
   if cosa=0 then exit(pi/2);

   sina:=sqrt(1-sqr(cosa));
   tana:=sina/cosa;
   exit(arctan(tana));

end;
function min(a,b:double):double;
begin
   if a<b then exit(a) else exit(b);
end;
function max(a,b:double):double;
begin
   if a>b then exit(a) else exit(b);
end;

function sector(a,r:double):double;
begin
   exit(a*r*r/2);
end;
function triangle(a,r:double):double;
begin
   exit(sin(a)*r*r/2);
end;
function inlside(s:circle;l:double):boolean;
begin
   if (s.x-s.r>l) or (abs(s.x-s.r-l)<le) then exit(true) else exit(false);
end;
function inrside(s:circle;r:double):boolean;
begin
   if (s.x+s.r<r) or (abs(s.x+s.r-r)<le) then exit(true) else exit(false);
end;

function intarea(s:circle;l,r:double):double;
var
   i,j:longint;
   a,a2,s1,s2,s3,s4:double;
   bl,br:boolean;
begin
   if (r<s.x-s.r) or (s.x+s.r<l) then exit(0);
   if (s.x<=l) then
   begin
      a:=arccos((l-s.x)/s.r)*2;
      if (abs(s.x-l)<le) then s1:=0
      else s1:=triangle(a,s.r);
      s2:=sector(a,s.r);

      if s.x+s.r>r then
      begin
         a:=arccos((r-s.x)/s.r)*2;
         s3:=sector(a,s.r);
         s4:=triangle(a,s.r);
         s2:=s2-(s3-s4);

      end;
      exit(s2-s1);
   end
   else
   if (s.x>=r) then
   begin
      a:=arccos((s.x-r)/s.r)*2;
      if (abs(s.x-r)<le) then s1:=0
      else s1:=triangle(a,s.r);
      s2:=sector(a,s.r);

      if s.x-s.r<l then
      begin
         a:=arccos((s.x-l)/s.r)*2;
         s3:=sector(a,s.r);
         s4:=triangle(a,s.r);
         s2:=s2-(s3-s4);

      end;
      exit(s2-s1);

   end
   else
   begin
      bl:=inlside(s,l);
      br:=inrside(s,r);
      if bl and br then exit(pi*s.r*s.r);
      if bl and not(br) then
      begin
         a:=arccos((r-s.x)/s.r)*2;
         s3:=sector(a,s.r)-triangle(a,s.r);
         exit(pi*s.r*s.r-s3);
      end;
      if not(bl) and br then
      begin
         a:=arccos((s.x-l)/s.r)*2;
         s3:=sector(a,s.r)-triangle(a,s.r);
         exit(pi*s.r*s.r-s3);
      end;

      a:=arccos((s.x-l)/s.r)*2;

      a2:=arccos((r-s.x)/s.r)*2;
      s1:=sector(2*pi-a-a2,s.r);
      s2:=triangle(a,s.r)+triangle(a2,s.r);
      exit(s1+s2);

   end;

end;
function place(k:longint;l,r:double):boolean;
var
   tot:double;
   i,j:longint;
begin
   tot:=0;
   for j:=1 to m[k] do
   begin
         tot:=tot+intarea(s[k,j],l,r);
   end;
//   writeln(tot*n,' ',wanted[k]*pi);

   if (abs(tot*n-wanted[k]*pi)<le) then exit(true);
   if (tot*n<(wanted[k]*pi)) then exit(false) else exit(true);
end;
function bsearch(r1,r2:double):double;
var
   m:double;
   i,j,k,num:longint;
   flag:boolean;
begin
   for k:=1 to 60 do
   begin
      flag:=false;
      m:=(r1+r2)/2;
      for i:=1 to n do
         if not b[i] then
         begin
            flag:=flag or place(i,l,m);
            if flag then
            begin
               num:=i;
               break;
            end;
         end;
      if flag then r2:=m else r1:=m;
   end;

   b[num]:=true;
   ans[num,1]:=l;
   ans[num,2]:=r1;

   exit(r1);

end;
begin
  { assign(input,'kingdom.in');
   reset(input);
  } r:=-10000;
   l:=10000;
   read(n);
   fillchar(b,sizeof(b),false);
   fillchar(wanted,sizeof(wanted),0);
   for i:=1 to n do
   begin
      read(m[i]);
      for j:=1 to m[i] do
      begin
         read(s[i,j].x,s[i,j].y,s[i,j].r);
 //        writeln(s[i,j].x,s[i,j].y,s[i,j].r);

         r:=max(r,s[i,j].x+s[i,j].r);
         l:=min(l,s[i,j].x-s[i,j].r);
         wanted[i]:=wanted[i]+sqr(s[i,j].r);

      end;
   end;
   r:=r+1;

   for i:=1 to n do
      l:=bsearch(l,r);

   for i:=1 to n do
   begin
      writeln('4');
      writeln(ans[i,1]:7:7,' 3000');
      writeln(ans[i,1]:7:7,' -3000');
      writeln(ans[i,2]:7:7,' -3000');
      writeln(ans[i,2]:7:7,' 3000');
   end;

//   close(input);
end.