poj1979
简单题
View Code
#include
<
iostream
>
#include
<
cstdio
>
#include
<
cstdlib
>
#include
<
cstring
>
#include
<
queue
>
using
namespace
std;
#define
maxn 25
struct
XPoint
{
int
x, y;
} a;
bool
map[maxn][maxn], vis[maxn][maxn];
int
n, m, ans;
int
dir[
4
][
2
]
=
{
{
0
,
1
},
{
0
,
-
1
},
{
1
,
0
},
{
-
1
,
0
} };
void
input()
{
for
(
int
i
=
0
; i
<
n; i
++
)
{
for
(
int
j
=
0
; j
<
m; j
++
)
{
char
ch;
scanf(
"
%c
"
,
&
ch);
if
(ch
==
'
#
'
)
map[i][j]
=
false
;
else
map[i][j]
=
true
;
if
(ch
==
'
@
'
)
{
a.x
=
i;
a.y
=
j;
}
}
getchar();
}
}
bool
ok(XPoint
&
a)
{
if
(a.x
<
0
||
a.y
<
0
||
a.x
>=
n
||
a.y
>=
m)
return
false
;
return
!
vis[a.x][a.y]
&&
map[a.x][a.y];
}
void
bfs()
{
memset(vis,
0
,
sizeof
(vis));
queue
<
XPoint
>
q;
q.push(a);
vis[a.x][a.y]
=
true
;
ans
=
0
;
while
(
!
q.empty())
{
XPoint a
=
q.front();
q.pop();
ans
++
;
XPoint b;
for
(
int
i
=
0
; i
<
4
; i
++
)
{
b.x
=
a.x
+
dir[i][
0
];
b.y
=
a.y
+
dir[i][
1
];
if
(ok(b))
{
q.push(b);
vis[b.x][b.y]
=
true
;
}
}
}
}
int
main()
{
//
freopen("t.txt", "r", stdin);
while
(scanf(
"
%d%d
"
,
&
m,
&
n), m
|
n)
{
getchar();
input();
bfs();
printf(
"
%d\n
"
, ans);
}
return
0
;
}