河边有：一只大老虎一只小老虎一只大狮子一只小狮子一只大豹子一只小豹子有一条船,一次最多只能载两只动物过河在以下条件下如何

ab到对岸 `````````` ab
2 a 回来 ```````````` a
3 ac到对岸``````````` abc
4 a回来 ``````````` bc
5 BC到对岸 `````````` BCbc
6 Bb回来 ``````````` Cc
7 Aa到对岸```````````ACac
8 Cc回来 ``````````` Aa
9 BC到对岸 ``````````ABCa
10 a回来 ``````````` ABC
11 ac到对岸 `````````` ABCac
12 B回来 ```````````` ACac
13 Bb到对岸`````````` ABCabc