What is the optimal time complexity of solving House Robber II?

The optimized solution achieves a time complexity of O(n) by using sorting, mathematical shortcuts, or hash table lookups.

What is the auxiliary space complexity for House Robber II?

The space complexity is O(1) since we only use a minimal/constant amount of extra memory for tracking variables (or auxiliary space if dynamic structures are allocated).

What are the typical edge cases we must handle in House Robber II?

Key edge cases include empty collections, negative or large bounds causing integer overflow, arrays with only one element, or inputs where target criteria are not met.

How can we optimize the brute force approach for House Robber II?

Brute force methods often inspect all possible combinations. We optimize this by sorting the input list to enable binary search, or tracking processed items in a set to avoid redundant nested loop lookups.

Back to Practice Dashboard

Top 150 InterviewMedium

House Robber II

Learn how to solve the 'House Robber II' problem. This detailed resource details brute force and optimized approaches.

Mode Selected

Problem Statement

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.

Write a function rob(nums: List[int]) -> int.

Constraints

•1 <= len(nums) <= 100
•0 <= nums[i] <= 1000

Examples

Example 1

Input

nums = [2,3,2]

Output

Explanation

You cannot rob house 1 and house 3 because they are adjacent in the circular layout.

Example 2

Input

nums = [1,2,3,1]

Output

Explanation

Rob house 1 (money = 1) and rob house 3 (money = 3). Total = 4.

Need a Hint?

Define subproblem states, establish the recurrence relation, and use memoization (top-down) or tabulation (bottom-up).

Edge Cases to Watch

Empty list or null input variables
Single item lists/arrays
Extremely large input bounds causing integer or stack overflow

Ready to Solve?

Open the problem in PyRun's browser-based Python editor. Your code runs fully offline — no server required.

Open in Editor