POJ 3009 Curling 2.0
解题思路:DFS
Bad
#include
<
iostream
>
using
namespace
std;
int
w, h, sx, sy, ex, ey, map[
20
][
20
];
const
int
dir[
4
][
2
]
=
{
0
,
1
,
1
,
0
,
0
,
-
1
,
-
1
,
0
};
inline
bool
IsOk(
int
&
x,
int
&
y,
int
d)
{
int
i,tx,ty;
for
(tx
=
x,ty
=
y,i
=
1
;;i
++
,tx
=
x,ty
=
y)
{
x
+=
dir[d][
0
],y
+=
dir[d][
1
];
if
(x
<
0
||
x
>=
h
||
y
<
0
||
y
>=
w)
return
false
;
if
(map[x][y]
==
1
){
if
(i
!=
1
){map[x][y]
=
0
;x
=
tx,y
=
ty;
return
true
;}
return
false
;}
if
(map[x][y]
==
3
)
return
true
;
}
}
int
DFS(
int
x,
int
y,
int
depth,
int
min)
{
int
i,j,d,tx,ty,mind
=
11
;
if
(depth
>
10
||
depth
>=
min)
return
depth;
if
(x
==
ex
&&
y
==
ey)
return
depth;
for
(i
=
0
;i
<
4
;i
++
)
{
tx
=
x, ty
=
y;
if
(IsOk(tx, ty, i))
{
d
=
DFS(tx, ty, depth
+
1
,mind);
if
(tx
!=
ex
||
ty
!=
ey)
map[tx
+
dir[i][
0
]][ty
+
dir[i][
1
]]
=
1
;
if
(mind
>
d)mind
=
d;
}
}
return
mind;
}
int
main()
{
int
i,j,d;
while
(scanf(
"
%d %d
"
,
&
w,
&
h)
&&
(w
+
h))
{
for
(i
=
0
;i
<
h;i
++
)
for
(j
=
0
;j
<
w;j
++
)
{
scanf(
"
%d
"
,
&
map[i][j]);
if
(map[i][j]
==
2
)sx
=
i,sy
=
j;
else
if
(map[i][j]
==
3
)ex
=
i,ey
=
j;
}
d
=
DFS(sx, sy,
0
,
11
);
d
>
10
?
printf(
"
-1\n
"
):printf(
"
%d\n
"
,d);
}
return
0
;
}