def Hnt(n, ch1, ch2, ch3):
if n == 1:
print(ch1, ‘-->‘, ch3)
else:
Hnt(n - 1, ch1, ch3, ch2)
print(ch1, ‘-->‘, ch3)
Hnt(n - 1, ch2, ch1, ch3)
N = int(input())
Hnt(N, ‘A‘, ‘B‘, ‘C‘)
原文：https://www.cnblogs.com/gtxy/p/12651736.html