Bitwise AND of Numbers Range
A medium-tier problem at 48% community acceptance, tagged with Bit Manipulation. Reported in interviews at Google and 0 others.
Bitwise AND of Numbers Range is a Medium-difficulty problem that's asked at Google and hits roughly half of candidates who attempt it. The problem looks straightforward: given a range, AND all numbers in it together. The trap is that you can't iterate through the range. Naive loops fail on large ranges like 1 to 2 billion. You need to see the bit-level pattern: what bits are guaranteed to stay 1 across the entire range. StealthCoder surfaces the exact trick if you blank during your live assessment.
Companies that ask "Bitwise AND of Numbers Range"
Bitwise AND of Numbers Range 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 by an Amazon engineer who watched the leaked-problem repo become an industry secret. He decided you should have it too.
Get StealthCoderThe key insight is that if a bit flips at any point in the range, it becomes 0 in the final AND. You're looking for which bit positions remain constant (and 1) from the left edge to the right edge. The algorithm removes the rightmost bit that differs between the left and right boundary, one at a time, until they're equal. This eliminates the iteration entirely and runs in O(log N) time. Most candidates either try brute force or don't recognize that bit differences at the boundary reveal where variability spreads. Bit Manipulation problems reward pattern recognition over implementation, and this one tests whether you can translate 'AND all numbers in a range' into 'find the common prefix bits'. If you hit this live and the pattern doesn't click, StealthCoder solves it invisibly in seconds.
Pattern tags
You know the problem.
Make sure you actually pass it.
Bitwise AND of Numbers Range 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 by an Amazon engineer who watched the leaked-problem repo become an industry secret. He decided you should have it too. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Bitwise AND of Numbers Range interview FAQ
Why can't I just loop through the range and AND the numbers?+
On large ranges (e.g., 1 to 2 billion), iteration times out. You need an O(log N) algorithm that works purely on bit positions. The problem tests whether you see that the AND result is determined by bit differences at the boundaries, not the count of numbers.
Is this problem actually asked at big tech companies?+
Yes, Google reports it. It's a genuine medium-tier Bit Manipulation filter. It's not common enough to be everywhere, but it's common enough that you should recognize the pattern if you prep on this topic.
What's the actual trick to solving this efficiently?+
Find the common bit prefix between left and right boundaries. Right-shift both until they're equal, counting shifts. That prefix, left-shifted back, is your answer. You're erasing bits that vary within the range because any variable bit ANDs to 0.
How does this relate to other Bit Manipulation problems?+
It combines bit analysis (finding which bits matter) with boundary logic (recognizing that range behavior is dictated by endpoints). If you've drilled XOR, AND, and bit counting, the underlying logic will feel familiar. It's a step up in pattern spotting.
How hard is this really, given it's Medium and ~48% acceptance?+
The median candidate either misses the bit-prefix insight and times out, or codes the right idea but has off-by-one bugs in the shift logic. It's not algorithmically complex, but it requires clear thinking under pressure. Acceptance rate reflects that.
Want the actual problem statement? View "Bitwise AND of Numbers Range" on LeetCode →