记录编号	4589	评测结果	AATTAAAATA
题目名称	[NOI 1999]棋盘分割	最终得分	70
用户昵称	bing	是否通过	未通过
代码语言	Pascal	运行时间	6.747 s
提交时间	2008-10-21 13:30:18	内存使用	0.11 MiB

program bing;
type
 kuai=record
 x1,x2,y1,y2:integer;
end;
var
 f1,f2:text;
 n:integer;
 s:real;
 a:array[1..15] of kuai;
 b:array[1..8,1..8]of real;
procedure init;
var
 i,j:Integer;
begin
 assign(f1,'division.in');reset(f1);
 assign(f2,'division.out');rewrite(f2);
 readln(f1,n);
 s:=640000;
 for i:=1 to 8 do
  for j:=1 to 8 do
  read(f1,b[i,j]);
 a[1].x1:=1;a[1].y1:=1;
 a[1].x2:=8;a[1].y2:=8;
end;
procedure qiu;
var
 i,j,x:Integer;
 c:array[1..15] of real;
 p,q:real;
begin
 fillchar(c,sizeof(c),0);
 for x:=1 to n do
 begin
 c[x]:=0;
 for i:=a[x].x1 to a[x].x2 do
 for j:=a[x].y1 to a[x].y2 do
 c[x]:=c[x]+b[i,j];
 end;
 p:=0;q:=0;
 for i:=1 to n do p:=p+c[i];
 p:=p/n;
 for i:=1 to n do q:=q+sqr(c[i]-p);
 q:=q/n;
 if q<s then s:=q;
end;
procedure nb(x:integer);
var
 i,j,k:Integer;
begin
 for i:=1 to x-1 do
 begin
  for j:=a[i].x1 to a[i].x2-1 do
  begin
   k:=a[i].x2;
   a[x].x1:=j+1;a[x].y1:=a[i].y1;
   a[x].x2:=a[i].x2;a[x].y2:=a[i].y2;
   a[i].x2:=j;
   if x=n then qiu else
   nb(x+1);
   a[i].x2:=k;
  end;
  for j:=a[i].y1 to a[i].y2-1 do
  begin
   k:=a[i].y2;
   a[x].y1:=j+1;a[x].x1:=a[i].x1;;
   a[x].y2:=a[i].y2;a[x].x2:=a[i].x2;
   a[i].y2:=j;
   if x=n then qiu else
   nb(x+1);
   a[i].y2:=k;
  end;
 end;
end;
begin
 init;
 nb(2);
 write(f2,sqrt(s):0:3);
 close(f1);close(f2);
end.