【LeetCode】213. House Robber II

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class Solution:
    # 分为两种情况，数组包含range(0~len-1)和数组包含range(1~len)，每种情况使用DP求解，最后结果为两种情况的最大值
    def rob(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        if not nums:
            return 0
        elif len(nums) == 1:
            return nums[0]
        elif len(nums) == 2:
            return max(nums[0], nums[1])
        else:
            opt = []
            opt.append(nums[0])
            opt.append(max(nums[0], nums[1]))
            opt1 = []
            opt1.append(nums[1])
            opt1.append(max(nums[1], nums[2]))
            
            for i in range(2, len(nums)-1):
                A = opt[i-2] + nums[i]
                B = opt[i-1]
                opt.append(max(A, B))
                A1 = opt1[i-2] + nums[i+1]
                B1 = opt1[i-1]
                opt1.append(max(A1, B1))
                
            return max(opt[-1], opt1[-1])


class Solution:
    # 简化一下写法
    def divrob(self, nums):
        opt = []
        opt.append(nums[0])
        opt.append(max(nums[0], nums[1]))
        for i in range(2, len(nums)):
            opt.append(max(opt[i-2] + nums[i], opt[i-1]))
        return opt[-1]
    
    def rob(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        if not nums:
            return 0
        elif len(nums) == 1:
            return nums[0]
        elif len(nums) == 2:
            return max(nums[0], nums[1])
        else:
            return max(self.divrob(nums[1:]), self.divrob(nums[:-1]))