89. House Robber II

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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.

Constraints:

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Houses are circular: can't rob both first and last. Split into two cases: (1) rob houses 0..n-2, (2) rob houses 1..n-1. Apply House Robber I logic to each case and take maximum.

Time Complexity

O(n)

Space Complexity

O(1)