ok try again!

來源: 於 2010-01-26 17:51:47 [博客] [舊帖] [給我悄悄話] 本文已被閱讀：次

1 and 2 cross 2 min
2 come back 2 min
5 and 10 cross 10 min
1 come back 1 min
1 and 2 cross 2 min
-------------------------
17 min
My old way is faster to think than this one. ;)