入门（NDK1329）

算法：搜索

分析：裸的搜索，怎么搜都不会超时。

program SH1329;

const dx:array [1..4] of -1..1=(-1,0,1,0);
      dy:array [1..4] of -1..1=(0,1,0,-1);

var
 w,h,x,y,tot:longint;
 a:array [-1..20,-1..20] of 0..2;
 d:array [-1..1000,-1..2] of longint;

procedure init;
var
 i,j:longint;
 ch:char;
begin
 tot:=1;
 readln(w,h);
 for i:=1 to h do
  begin
   for j:=1 to w do
    begin
     read(ch);
     case ch of
      '.':a[i,j]:=1;
      '#':a[i,j]:=2;
      '@':begin a[i,j]:=1; x:=i; y:=j; end;
     end;
    end;
   readln;
  end;
end;

procedure bfs;
var
 i,j,head,t,x1,y1:longint;
begin
 head:=0; t:=1; d[1,1]:=x; d[1,2]:=y; a[x,y]:=2;
 while head<t do
  begin
   inc(head);
   for i:=1 to 4 do
    begin
     x1:=d[head,1]+dx[i];
     y1:=d[head,2]+dy[i];
     if (a[x1,y1]=1) and (x1>=1) and (x1<=h) and (y1>=1) and (y1<=w) then
      begin
       inc(tot);
       inc(t);
       d[t,1]:=x1;
       d[t,2]:=y1;
       a[x1,y1]:=2;
      end;
    end;
  end;
end;

begin
 assign(input,'NDK1329.in'); reset(input);
 assign(output,'NDK1329.out'); rewrite(output); 

 init;
 bfs;
 writeln(tot);
 
 close(input); close(output);
end.