l = ['a', 'b', 'c']
def f(lt, start, end):
if start == end:
print(lt)
else:
for i in range(start, end+1):
lt[start], lt[i] = lt[i], lt[start]
f(lt, start+1, end)
lt[start], lt[i] = lt[i], lt[start]
if __name__ == '__main__':
f(l, 0, 2)
运行结果：
