At any time, the train can enter the exit from the entry station or directly from the entry, or from the station to the exit. That is to say, at any time, a car can drive along the direction of arrow a or B or C. Now there are some cars waiting at the entrance. They will exit from the above way. Now you need to count all the possible outgoing sequences. For example, when the entry is ABC, the possible outgoing sequences are ABC, ACB, BAC, BCA and CBA.

Filename	Size	Update
Station.cpp	2487	2018-01-05

• We are an exchange download platform that only provides communication channels. The downloaded content comes from the internet. Except for download issues, please Google on your own.
• The downloaded content is provided for members to upload. If it unintentionally infringes on your copyright, please contact us.
• Please use Winrar for decompression tools
• If download fail, Try it againg or Feedback to us.
• If downloaded content did not match the introduction, Feedback to us，Confirm and will be refund.
• Before downloading, you can inquire through the uploaded person information

Nothing．