House Robber IV
A medium-tier problem at 65% community acceptance, tagged with Array, Binary Search, Dynamic Programming. Reported in interviews at Cashfree and 1 others.
House Robber IV shows up in assessments at LinkedIn and Cashfree, and it's the kind of problem where the greedy intuition tanks you hard. You see an array of house values and think dynamic programming, standard robber problem. Wrong. The trick is binary search on the answer space, paired with a greedy validity check. This is a 60% acceptance rate problem, meaning half the candidates submitting either TLE on brute force or misread the constraint entirely. If this lands in your live OA and you blank on the binary search angle, StealthCoder surfaces a working solution in seconds while the proctor sees only your screen.
Companies that ask "House Robber IV"
House Robber IV is the kind of problem that decides whether you pass. StealthCoder reads the problem on screen and surfaces a working solution in under 2 seconds. Invisible to screen share. The proctor sees nothing. Made for the engineer who has done the work but might still blank with a webcam pointed at him.
Get StealthCoderThe problem asks you to rob houses with a constraint: the maximum value you steal can't exceed some threshold. The naive move is trying every subset of non-adjacent houses and tracking maximum values. That fails instantly on larger inputs. The actual pattern is binary searching the answer (the max house value you'll rob), then greedily checking if you can steal at least k houses while staying under that value. Each check runs in linear time, so you get O(n log n) total. Most candidates either miss the binary search entirely and get stuck on DP recurrence, or they correctly identify binary search but write the greedy check wrong, counting houses instead of validating the constraint. The four topics listed (Array, Binary Search, Dynamic Programming, Greedy) all touch this problem; Binary Search is the key. When you're stuck live, StealthCoder skips the false starts and lands on the binary search structure immediately.
Pattern tags
You know the problem.
Make sure you actually pass it.
House Robber IV recycles across companies for a reason. It's medium-tier, and most candidates blank under the timer. StealthCoder is the hedge: an AI overlay invisible during screen share. It reads the problem and surfaces a working solution in under 2 seconds. Made for the engineer who has done the work but might still blank with a webcam pointed at him. Works on HackerRank, CodeSignal, CoderPad, and Karat.
House Robber IV interview FAQ
Is House Robber IV actually asked at big companies?+
LinkedIn and Cashfree have confirmed asks. It's not a household-name FAANG staple, but it's popular enough that you should know the pattern. If binary search + greedy optimization isn't in your toolkit yet, this problem teaches it fast.
What's the trick that most people miss?+
Treating it like a standard DP robber problem instead of recognizing it as a binary search problem. The constraint isn't "maximize total steal", it's "steal exactly k houses under a max value." That shift makes binary search the right tool, not DP.
Why doesn't greedy alone work?+
You can't greedily pick the k smallest houses and call it done. You also need the non-adjacent constraint. Binary search on the answer, then greedily validate that you can pick k non-adjacent houses all below your candidate value. The validation step is O(n), search is O(log n).
How does this relate to the other four topics listed?+
Array is the input structure. Dynamic Programming is the false path many take. Binary Search is the real solution. Greedy is the validation inside your binary search. Knowing which topic leads is what separates 60% acceptance from the 40% that TLE or wrong-answer.
How long should this take in a real OA?+
If you know the binary search pattern, 15 to 20 minutes. If you start with DP and realize halfway through it's wrong, you're looking at 40+ and possibly running out of time. That's where a live solution matters most.
Want the actual problem statement? View "House Robber IV" on LeetCode →