# -*- coding: utf-8 -*-

class Solution:

# @param nums: A list of non-negative integers.

# return: an integer

def houseRobber2(self, nums):

# write your code here

'''

与打劫房屋相比：

1. 如果我抢了第1间，最后一间就不能抢。

2. 如果第一间不抢，就可以抢最后一间。

'''

if not nums:

return 0

elif len(nums) == 1:

return nums[0]

elif len(nums) == 2:

return max(nums[0], nums[1])

else:

ret_1, ret_2 = 0, 0

# 场景1

caches = nums[:]

caches[1] = max(caches[0], caches[1])

for i in xrange(2, len(nums) - 1):

caches[i] = max(caches[i] + caches[i - 2], caches[i - 1])

ret_1 = caches[-2]

caches = nums[:]

caches[0] = 0

for i in xrange(2, len(nums)):

caches[i] = max(caches[i] + caches[i - 2], caches[i - 1])

ret_2 = caches[-1]

return max(ret_1, ret_2)