Largest Combination With Bitwise AND Greater Than Zero
A medium-tier problem at 81% community acceptance, tagged with Array, Hash Table, Bit Manipulation. Reported in interviews at Jump Trading and 0 others.
Jump Trading's been running this one through their OA pipeline and candidates either nail it or tank it hard. The problem asks you to find the largest subset of an array where the bitwise AND of all elements is greater than zero. High acceptance rate (81%) masks a real gotcha: most people brute-force every subset and hit time limits, or they misunderstand what AND-greater-than-zero actually means. The trick isn't about subset size alone. It's about realizing which bits must survive the AND operation and building from there. If you hit this live and blank on the pattern, StealthCoder solves it in seconds invisible to the proctor.
Companies that ask "Largest Combination With Bitwise AND Greater Than Zero"
Largest Combination With Bitwise AND Greater Than Zero 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. Built by an Amazon engineer who used it to pass JPMorgan's OA and system design loop.
Get StealthCoderThe trap is thinking you can just greedily pick the largest k elements. You can't. AND is brutal; one element with a zero bit kills that bit for the entire subset. The real approach: every valid subset must share at least one common set bit across all its members. Start by counting how often each bit position appears. Then iterate through candidate bit masks, finding which bits are set in enough elements to form a large subset. Hash tables let you group elements by their bitmasks efficiently. The problem lives in Bit Manipulation and Counting for good reason. Common failure: iterating all 2^n subsets when n is large. Another trap: forgetting that even a single element with AND greater than zero (i.e., nonzero) counts as valid. When you're under live pressure and the pattern isn't clicking, StealthCoder runs invisibly during assessment and surfaces a working solution fast.
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Largest Combination With Bitwise AND Greater Than Zero 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. Built by an Amazon engineer who used it to pass JPMorgan's OA and system design loop. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Largest Combination With Bitwise AND Greater Than Zero interview FAQ
What does 'bitwise AND greater than zero' actually mean?+
The AND result must be nonzero, meaning at least one bit position must be set to 1 across all elements in your subset. If every bit ends up 0, the AND is zero and the subset is invalid. That's why single nonzero elements are always valid subsets.
Why can't I just pick the largest k elements?+
Because AND is strict. If the five largest elements happen to AND to zero (which happens when they don't share a common set bit), they're worthless. A smaller subset that shares a common bit will always beat them. You must respect bit overlap, not just count.
How does Hash Table help here?+
Group elements by their bitmask. Elements with identical bitmasks will always AND together to produce that same mask. This avoids redundant calculation and helps you quickly identify which bit patterns are present in your input. Counting occurrences tells you subset size for each candidate mask.
Is this still asked at quant trading firms?+
Jump Trading included it in recent cycles, yes. Quant and high-frequency shops love bit manipulation problems because they test low-level thinking and efficiency. Expect it if you're interviewing at firms that care about bitwise optimization.
What's the main pitfall under interview pressure?+
Defaulting to brute force: generate all subsets, compute AND, track max. This works for tiny arrays but explodes at n=20 or higher. The real solution pivots: iterate candidate bit masks (at most 30-32 for typical integers), then for each mask, find how many array elements have all those bits set. That's polynomial, not exponential.
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