Description
一个字符矩阵，'.'为海洋，'A'为主岛，'x'为其它岛，保证所有'A'构成一个联通块，画一个圈，使得所有的'A'在圈内，所有的'x'在圈外，更具体的看样例，求这样的圈的最小周长Input
Line 1: Two space-separated integers: H and W * Lines 2..H+1: Line i+1 contains contains W characters that are the elements of map row i (all '.' or 'x' or 'A')Output
* Line 1: The minimum length of a path that Farmer John's cruise ship can takeSample Input
12 19...................
...................
.....A.............
.....A..x..........
..x..A.....AAAA....
.....A.....A..A....
.....AAAAAAAA.A....
........A.....A....
.xx...AAA...x.A....
......A............
...AAAAAAAAAAAAA...
...................
