pku1468 Rectangles

这道题真是没法说，时间限制是5000ms，而且矩形数还少于5000，

O(n^2)枚举即可啊！！

program pku1468(input,output);
type
   node    = record
         x1,y1,x2,y2 : longint;
      end;
var
   a        : array[0..5001] of node;
   answer,n : longint;
function cover(x,y :longint ):boolean;
begin
   if (a[y].x1<=a[x].x1)and(a[x].x2<=a[y].x2) then
      if (a[y].y1<=a[x].y1)and(a[x].y2<=a[y].y2) then
     exit(true);
   exit(false);
end; { cover }
procedure init;
var
   i : longint;
begin
   readln(n);
   for i:=1 to n do
      readln(a[i].x1,a[i].x2,a[i].y1,a[i].y2);
end; { init }
procedure main;
var
   i,j : longint;
begin
   answer:=0;
   for i:=1 to n do
   begin
      for j:=1 to n do
     if i<>j then 
        if cover(i,j) then
        begin
           inc(answer);
           break;
        end;
   end;
end; { main }
begin
   while not eof do
   begin
      init;
      main;
      writeln(answer);
   end;
end.