198. House Robber

https://leetcode.com/problems/house-robber/description/

Description

You are a professional robber planning to rob houses along a street. Each house has a certain amount of money stashed, the only constraint stopping you from robbing each of them is that adjacent houses have security system connected and it will automatically contact the police if two adjacent houses were broken into on the same night.

Given a list of non-negative integers representing the amount of money of each house, determine the maximum amount of money you can rob tonight without alerting the police.

Example 1:
Input: [1,2,3,1]
Output: 4
Explanation: Rob house 1 (money = 1) and then rob house 3 (money = 3).
Total amount you can rob = 1 + 3 = 4.

Example 2:

Input: [2,7,9,3,1]
Output: 12
Explanation: Rob house 1 (money = 2), rob house 3 (money = 9) and rob house 5 (money = 1).
Total amount you can rob = 2 + 9 + 1 = 12.

Solution

使用动态规划，递归解决该问题：

class Solution:
    def rob_result(self, n):
        if n in self.result:
            return self.result[n]
        cur_result = max(self.rob_result(n-1),
                        self.nums[-n]+self.rob_result(n-2))
        self.result[n] = cur_result
        return cur_result
    def rob(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        self.nums = nums
        if len(nums)==0:return 0
        self.result = {0:0, 1:nums[-1]}
        return self.rob_result(len(nums))