House Robber
Description: Given money in houses standing in a row, you cannot rob two adjacent houses. Return the maximum amount you can take.
Example 1:
Input: nums = [2,7,9,3,1]
Output: 12
Example 2:
Input: nums = [1,2,3,1]
Output: 4
Constraints:
1 <= nums.length <= 100
0 <= nums[i] <= 400
Recommended time and space complexity
Aim for O(n) time and O(1) space.
Hint 1
For each house there are two options: rob it or skip it.
Hint 2
Robbing house i adds the best result up to i−2; skipping takes the best up to i−1.
Hint 3
Only two previous values are needed — no array required.