After ACed this terrible problem, I made a small prog that may help you guys debug.
It can create random test data and auto check whether your prog gives right answer.

http://www.rayfile.com/en/files/6d44e53d-a425-11de-9ad8-0014221b798a/
http://www.rayfile.com/files/6d44e53d-a425-11de-9ad8-0014221b798a/

Just give it a try. If it doesn't work... Or any comments, write here, I'll check this thread up sometimes.
BTW, forgive my poor English.

Edited by author 21.09.2009 20:00

Edited by author 21.09.2009 20:01

For all the copypaste aficionados: the sample given is

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...........┌─────┐................................
...........│.....│................................
....┌──────│.....│..........┌─┐...................
....│......│.....│..........│.│...................
....│......│.....│..........└─┘...................
....│......│....┌│────┐.............┌─┐...........
....│......└─────┘....│.............│.│...........
....│......│....│.....│.............└─┘...........
....│......│....│.....│.........┌──┐..............
....└──────┘....│.....│.........│..│..............
................│.....│.........│..│..............
................└─────┘.........└──┘..............
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