day_39

198. 打家劫舍

class Solution:def rob(self, nums: List[int]) -> int:if len(nums) == 1:return nums[0]dp = [0] * len(nums)dp[0], dp[1] = nums[0], max(nums[0], nums[1])for i in range(2, len(nums)):dp[i] = max(dp[i - 1], dp[i - 2] + nums[i])return dp[len(nums) - 1]

213. 打家劫舍 II

class Solution:def rob(self, nums: List[int]) -> int:if len(nums) <= 2:return max(nums)def get_dp(nums):if len(nums) == 1:return nums[0]n = len(nums)dp = [0] * ndp[0], dp[1] = nums[0], max(nums[0], nums[1])for i in range(2, n):dp[i] = max(dp[i - 1], dp[i - 2] + nums[i])return dp[n - 1]return max(get_dp(nums[:-1]), get_dp(nums[1:]))

337. 打家劫舍 III

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right``
class Solution:def rob(self, root: Optional[TreeNode]) -> int:return max(self.traversal(root))def traversal(self, node):if not node:return (0, 0)left = self.traversal(node.left)right = self.traversal(node.right)val_0 = max(left) + max(right)val_1 = node.val + left[0] + right[0]return val_0, val_1

这题目自己想不出来，但是讲过之后，看了代码知道了意思，但是过一段时间，恐怕会忘。