记录编号	4910	评测结果	AATTAAAATA
题目名称	[NOI 1999]棋盘分割	最终得分	70
用户昵称	rottenwood	是否通过	未通过
代码语言	Pascal	运行时间	6.699 s
提交时间	2008-10-23 13:32:15	内存使用	0.11 MiB

program division;
type
shuzu=array[1..8,1..8] of integer;
shuzu1=array[1..15,1..4] of integer;
var
f:shuzu1;
s:shuzu;
i,j,k,m,n:longint;
ans,ba:real;
function zhaomin(x,y:real):real;
  begin
   if x>y then zhaomin:=y
          else zhaomin:=x;
          end;
function jisuan:real;
 var
 i,j,k:integer;
 a:array[1..15] of real;
 c:real;
 begin
 for i:=1 to 15 do a[i]:=0;
  for k:=1 to n do
    begin
    c:=0;
     for i:=f[k,1] to f[k,3]-1 do
      for j:=f[k,2] to f[k,4]-1 do
        c:=c+s[i,j];
        a[k]:=c;
    end;
    c:=0;
    for k:=1 to n do
    c:=c+(a[k]-ba)*(a[k]-ba);
    jisuan:=sqrt(c/n);
  end;
procedure dg(t:integer);
  var
   i,j,k,temp:integer;
   begin
   if t<n then
     BEGIN
   for k:=1 to t do
   begin
     for i:=f[k,1]+1 to f[k,3]-1 do
       begin
       f[t+1,1]:=i;f[t+1,2]:=f[k,2];
       f[t+1,3]:=f[k,3];f[t+1,4]:=f[k,4];
       f[k,3]:=i;
       dg(t+1);
       f[k,3]:=f[t+1,3];
       end;
     for j:=f[k,2]+1 to f[k,4]-1 do
       begin
       f[t+1,1]:=f[k,1];f[t+1,2]:=j;
       f[t+1,3]:=f[k,3];f[t+1,4]:=f[k,4];
       f[k,4]:=j;
       dg(t+1);
       f[k,4]:=f[t+1,4];
       end;
    end;
      end
      else
      ans:=zhaomin(ans,jisuan);
      end;
begin
assign(input,'division.in');reset(input);
assign(output,'division.out');rewrite(output);
readln(n);
for i:=1 to 8 do
   begin
   for j:=1 to 8 do  begin
    read(s[i,j]); ba:=ba+s[i,j]; end;
    readln;
    end;
    ans:=maxint;   ba:=ba/n;
    f[1,1]:=1; f[1,2]:=1; f[1,3]:=9; f[1,4]:=9;
dg(1);
writeln(ans:0:3);
close(output);
end.