House Robber

#using 3 vars
class Solution:
    def rob(self, nums: List[int]) -> int:
        prev1 = prev2 = prev3 = 0

        for i in nums:
            prev1, prev2, prev3 = max(prev2, prev3) + i, prev1, prev2

        return max(prev1, prev2)

#using two vars such that a = max(prev1, prev2) & b = max(prev2, prev3)
"""
class Solution:
    def rob(self, nums: List[int]) -> int:
        a, b = 0, 0

        for i in nums:
            a, b = max(b + i, a), a

        return a
"""