# 代码
l = [1, 4, 6, 9, 13, 16, 19, 28, 40]
print(l)
length = len(l)
for i in range(1,length//2):
	l[i-1],l[-i]=l[-i],l[i-1]
print(l)
# 输出
[1, 4, 6, 9, 13, 16, 19, 28, 40]
[40, 28, 19, 9, 13, 16, 6, 4, 1]