动态规划_leetcode198拓展

#coding=utf-8
# 1
# 对状态的定义 ： 考虑偷取[x...n-1]范围里的房子


class Solution1(object):
    def rob(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """

        if not nums:
            return 0


        length = len(nums)

        if length == 1:
            return  nums[0]

        memo = [-1 for i in range(length)]
        memo[length-1] = nums[length-1]

        for i in range(length-2 ,-1 ,-1):
            for j in range(i,length):
                if j+2 < length:
                    memo[i] = max(memo[i],nums[j] + memo[j+2])
                else:
                    memo[i] = max(memo[i],nums[j])

        return memo[i]


# 2
# 对状态的定义： 考虑偷取[0...x]范围里的房子

class Solution2(object):
    def rob(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """

        if not nums:
            return 0


        length = len(nums)

        if length == 1:
            return  nums[0]

        memo = [-1 for i in range(length)]
        memo[0] = nums[0]

        for i in range(1,length):
            for j in range(i,-1,-1):

                if j-2 >=0:
                    memo[i] = max(memo[i],nums[j] + memo[j-2])
                else:
                    memo[i] = max(memo[i],nums[j])


        return memo[length-1]


s = Solution2()
nm = [1,2,3,1]
print  s.rob(nm)