2021-01-05 Python百日打卡学习自【夸可编程】

题目：
翻转list，要求不使用新的list，只能在原list上完成
例子：
None -> None
[] -> []
[1,2,3,4] -> [4,3,21]
['a', 'b', 'c'] -> ['c', 'b', 'a']

def reverseList(chars):
    if chars is None:
        return None
    if len(chars) <= 1:
        return chars

    index = len(chars)//2
    for i in range(index):
        chars[i], chars[-i-1] = chars[-i-1], chars[i]
    return chars


alist = [1,2,3,4,5]
blist = [4]
clist = None

print(reverseList(alist))