hoj1195
双向广度优先搜索，本来是想哪个节点少扩展哪个，但是有一个问题，就是有可能上端的x层节点扩展出x+1层，下端的y层扩展出y+1层，这两个+1层有重合，便直接跳出，输出x+y+1，这样可能导致错误，因为x层节点并没有完全扩展完毕，很可能接下来要扩展的x层节点会扩展出的x+1层节点直接与y层节点重合。
View Code
#include
<
iostream
>
#include
<
cstdio
>
#include
<
cstdlib
>
#include
<
cstring
>
#include
<
queue
>
using
namespace
std;
struct
Node
{
int
lock
[
4
];
int
depth;
}s, e;
int
qnum[
3
], ans;
int
hash[
3
][
10
][
10
][
10
][
10
];
void
getin(
int
a[],
char
*
st)
{
for
(
int
i
=
0
; i
<
4
; i
++
)
a[i]
=
st[i]
-
'
0
'
;
}
bool
hashit(Node
&
a,
int
flag)
{
if
(hash[flag][a.
lock
[
0
]][a.
lock
[
1
]][a.
lock
[
2
]][a.
lock
[
3
]]
==
-
1
)
{
hash[flag][a.
lock
[
0
]][a.
lock
[
1
]][a.
lock
[
2
]][a.
lock
[
3
]]
=
a.depth;
if
(hash[
3
-
flag][a.
lock
[
0
]][a.
lock
[
1
]][a.
lock
[
2
]][a.
lock
[
3
]]
!=
-
1
)
ans
=
a.depth
+
hash[
3
-
flag][a.
lock
[
0
]][a.
lock
[
1
]][a.
lock
[
2
]][a.
lock
[
3
]];
return
true
;
}
return
false
;
}
void
extend(queue
<
Node
>
&
q,
int
flag)
{
qnum[flag]
--
;
Node temp
=
q.front();
//
printf("%d %d %d %d %d\n", temp.depth, temp.lock[0], temp.lock[1], temp.lock[2], temp.lock[3]);
q.pop();
temp.depth
++
;
for
(
int
i
=
0
; i
<
3
; i
++
)
{
swap(temp.
lock
[i], temp.
lock
[i
+
1
]);
if
(hashit(temp, flag))
{
q.push(temp);
qnum[flag]
++
;
}
swap(temp.
lock
[i], temp.
lock
[i
+
1
]);
}
for
(
int
i
=
0
; i
<
4
; i
++
)
{
temp.
lock
[i]
++
;
if
(temp.
lock
[i]
>
9
)
temp.
lock
[i]
-=
9
;
if
(hashit(temp, flag))
{
q.push(temp);
qnum[flag]
++
;
}
temp.
lock
[i]
--
;
if
(temp.
lock
[i]
<
1
)
temp.
lock
[i]
+=
9
;
temp.
lock
[i]
--
;
if
(temp.
lock
[i]
<
1
)
temp.
lock
[i]
+=
9
;
if
(hashit(temp, flag))
{
q.push(temp);
qnum[flag]
++
;
}
temp.
lock
[i]
++
;
if
(temp.
lock
[i]
>
9
)
temp.
lock
[i]
-=
9
;
}
}
void
work()
{
memset(hash,
-
1
,
sizeof
(hash));
qnum[
2
]
=
1
;
qnum[
1
]
=
1
;
queue
<
Node
>
q1, q2;
q1.push(s);
q2.push(e);
hashit(s,
1
);
hashit(e,
2
);
int
d1
=
0
;
int
d2
=
0
;
while
(
!
q1.empty()
||
!
q2.empty())
{
if
(qnum[
1
]
<
qnum[
2
]
&&
qnum[
1
]
!=
0
)
{
while
(q1.front().depth
==
d1)
extend(q1,
1
);
d1
=
q1.front().depth;
}
else
{
while
(q2.front().depth
==
d2)
extend(q2,
2
);
d2
=
q2.front().depth;
}
if
(ans
!=
-
1
)
return
;
}
}
void
input()
{
char
st1[
5
], st2[
5
];
ans
=
-
1
;
scanf(
"
%s
"
, st1);
scanf(
"
%s
"
, st2);
if
(strcmp(st1, st2)
==
0
)
{
ans
=
0
;
return
;
}
getin(s.
lock
, st1);
getin(e.
lock
, st2);
s.depth
=
0
;
e.depth
=
0
;
work();
}
int
main()
{
//
freopen("D:\\t.txt", "r", stdin);
int
t;
scanf(
"
%d
"
,
&
t);
while
(t
--
)
{
input();
printf(
"
%d\n
"
, ans);
}
return
0
;
}