老鼠 瓶
1 123
2 456
3 789
4 147
5 258
6 369
no need to test the 10th bottle
if poison is in 1 and 2, rats 1 4 5 would die. if poison is in 2 and 5, rats
1 2 5 would die. if poison is in 3 and 9, rats 1 3 6 would die.
if poison is in 5 and 10, only rats 2 and 5 would die, and you know the
other poison bottle is the 10th bottle