Maximum XOR After Operations
A medium-tier problem at 79% community acceptance, tagged with Array, Math, Bit Manipulation. Reported in interviews at American Express and 0 others.
Maximum XOR After Operations is a medium-difficulty problem that combines bit manipulation with greedy thinking. You're handed an array and a budget of operations, and you need to maximize the XOR of the final state. American Express has asked this one. The trick isn't immediately obvious: most candidates build a brute-force search or miss that certain bit positions can be controlled independently. The acceptance rate sits just under 80 percent, which means plenty of people solve it, but plenty also stall on the greedy insight. If this problem surfaces on your assessment and you blank on how to attack it, StealthCoder runs invisibly and surfaces a working solution in seconds.
Companies that ask "Maximum XOR After Operations"
Maximum XOR After Operations 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 core insight is that XOR operates bit by bit, so you can think about each bit position separately. The greedy move is to maximize higher-order bits first because they contribute more to the final value. A common wrong turn is trying to simulate every possible sequence of operations, which spirals into exponential complexity. Instead, you determine which bit positions are reachable given your operation budget, then construct the maximum XOR by setting the highest bits you can reach. The pattern sits at the intersection of Array iteration, Math (specifically bit weight and greedy selection), and Bit Manipulation (understanding XOR properties). During a live OA, if you get stuck on why your simulation approach is too slow, StealthCoder cuts through the noise and shows you the greedy construction that actually works.
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Maximum XOR After Operations 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.
Maximum XOR After Operations interview FAQ
Is this harder than typical bit manipulation problems?+
Not harder, just different. Standard XOR problems ask you to find pairs or compute subsets. This one requires you to think about what states are reachable and optimize greedily. The bit manipulation itself is straightforward once you see the greedy structure.
What's the main pitfall?+
Trying to brute-force or simulate all operation sequences. The real pattern is that higher-order bits dominate the final XOR value, so you work top-down and check what's achievable within your operation budget, then set bits greedily.
Do I need to know advanced bit tricks?+
No. You need to understand that XOR operates independently on each bit, that higher bits matter more in the final value, and basic bit masking. The hard part is spotting the greedy insight, not executing fancy bit operations.
Is this problem still asked at American Express?+
It's on the record as an American Express question. Given the medium difficulty and clear algorithmic structure, it fits their interview style well. Don't assume it's outdated just because acceptance is high.
How does this relate to other bit manipulation topics?+
This problem treats bit positions as independent optimization targets, which appears in problems about maximizing XOR pairs or subset sums. The array and budget constraints add a resource-allocation layer that forces the greedy approach.
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