213. House Robber II

Medium


You are a professional robber planning to rob houses along a street. Each house has a certain amount of money stashed. All houses at this place are arranged in a circle. That means the first house is the neighbor of the last one. Meanwhile, adjacent houses have a security system connected, and it will automatically contact the police if two adjacent houses were broken into on the same night.

Given an integer array nums representing the amount of money of each house, return the maximum amount of money you can rob tonight without alerting the police.

 

Example 1:

Input: nums = [2,3,2]
Output: 3
Explanation: You cannot rob house 1 (money = 2) and then rob house 3 (money = 2), because they are adjacent houses.

Example 2:

Input: nums = [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 3:

Input: nums = [1,2,3]
Output: 3

 

Constraints:

  • 1 <= nums.length <= 100
  • 0 <= nums[i] <= 1000




 class Solution:
    def rob(self, nums: List[int]) -> int:


        if len(nums)==1:
            return nums[0]

        num0, num1 = 0,0


        for n in nums[:-1]:
            temp = max(num1, num0+n)
            num0 = num1
            num1 = temp

        m1 = num1
        num0, num1 = 0,0

        for n in nums[1:]:
            temp = max(num1, num0+n)
            num0 = num1
            num1 = temp
        return max(m1, num1)

Random Note


From python 3.7 dict guarantees that order will be kept as they inserted, and popitem will use LIFO order but we need FIFO type system. so we need OrderedDict which have popIten(last = T/F) for this req. One thing, next(iter(dict)) will return the first key of the dict