poj1164
bfs
View Code
#include
<
iostream
>
#include
<
cstdio
>
#include
<
cstdlib
>
#include
<
cstring
>
using
namespace
std;
#define
maxn 55
struct
Point
{
int
x, y;
}q[maxn
*
maxn];
int
n, m, ans;
int
map[maxn][maxn];
bool
vis[maxn][maxn];
int
dir[
4
][
2
]
=
{
{
0
,
-
1
},
{
-
1
,
0
},
{
0
,
1
},
{
1
,
0
} };
bool
ok(Point
&
p)
{
if
(p.x
<
0
||
p.y
<
0
||
p.x
>=
n
||
p.y
>=
m
||
vis[p.x][p.y])
return
false
;
return
true
;
}
void
bfs(
int
cx,
int
cy)
{
int
front
=
0
, rear
=
1
;
vis[cx][cy]
=
true
;
q[
0
].x
=
cx;
q[
0
].y
=
cy;
int
num
=
0
;
while
(front
!=
rear)
{
Point p
=
q[front
++
];
num
++
;
int
k
=
1
;
for
(
int
i
=
0
; i
<
4
; i
++
)
{
Point temp;
temp.x
=
p.x
+
dir[i][
0
];
temp.y
=
p.y
+
dir[i][
1
];
if
(
!
(k
&
map[p.x][p.y])
&&
ok(temp))
{
q[rear
++
]
=
temp;
vis[temp.x][temp.y]
=
true
;
}
k
<<=
1
;
}
}
ans
=
max(ans, num);
}
int
main()
{
//
freopen("t.txt", "r", stdin);
scanf(
"
%d%d
"
,
&
n,
&
m);
for
(
int
i
=
0
; i
<
n; i
++
)
for
(
int
j
=
0
; j
<
m; j
++
)
scanf(
"
%d
"
,
&
map[i][j]);
int
num
=
0
;
memset(vis,
0
,
sizeof
(vis));
ans
=
0
;
for
(
int
i
=
0
; i
<
n; i
++
)
for
(
int
j
=
0
; j
<
m; j
++
)
if
(
!
vis[i][j])
{
bfs(i, j);
num
++
;
}
printf(
"
%d\n%d\n
"
, num, ans);
return
0
;
}