00000000x
00000000x
------->x
0000000|x
<-------x
00000000x
x是边界，线是路径
by shi_shu_huan @ 2018-12-01 21:48:25
00000000x
00000000x
------------>x
0000000| x
<------------x
00000000x
x是边界，线是路径
emm，意外
by shi_shu_huan @ 2018-12-01 21:49:13
事实上有70%的数据有这种情况
by shi_shu_huan @ 2018-12-08 16:33:27