Minimum Number of Operations to Make Array XOR Equal to K
A medium-tier problem at 85% community acceptance, tagged with Array, Bit Manipulation. Reported in interviews at American Express and 0 others.
You've got an array and a target XOR value K. The problem asks you to find the minimum operations to make the array's total XOR equal to K. It sounds simple until you realize the operation isn't what you think it is. American Express has asked this one. The acceptance rate is solid at 85%, but that number masks a common misread: candidates often overthink the operation definition or miss the bit-level insight that collapses the problem. If this hits your live assessment and you blank on the pattern, StealthCoder solves it in seconds, invisible to the proctor.
Companies that ask "Minimum Number of Operations to Make Array XOR Equal to K"
Minimum Number of Operations to Make Array XOR Equal to K 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 realized the OA tests how well you memorized 200 problems, not how well you code.
Get StealthCoderThe real trick here is understanding what operation you're allowed to perform. Most candidates assume you can flip bits or do something complex. In reality, the operation is usually a constrained one, and once you lock that down, the problem becomes a bit-counting exercise. You're looking at Bit Manipulation fundamentals: track XOR state as you iterate the array, recognize which bits are set in the current XOR versus the target K, and count the minimum flips needed. The pitfall is assuming you can modify any bit at any time. You can't. The operation is specific, and that specificity is what makes this medium, not easy. If you hit this under time pressure and the operation definition isn't clicking, StealthCoder runs invisibly during screen share and surfaces the working solution so you move forward.
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Minimum Number of Operations to Make Array XOR Equal to K 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 realized the OA tests how well you memorized 200 problems, not how well you code. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Minimum Number of Operations to Make Array XOR Equal to K interview FAQ
Is this really a medium problem or did American Express misrate it?+
The 85% acceptance rate suggests many candidates find it straightforward once they understand the operation constraint. The difficulty spike is frontloaded: if you misread what operation you can perform, you'll spiral. Once that's clear, it's a linear scan with XOR math. American Express data confirms it's asked and solved often.
What's the Bit Manipulation angle that makes this different from a standard XOR problem?+
You're not just computing XOR in isolation. You're tracking which bits differ between your current XOR and target K, then counting operations to flip only those bits. It's a bit-by-bit comparison problem disguised as an array operation. Bit Manipulation here means understanding which bits matter and how many changes they cost.
How do I avoid the most common wrong approach?+
Don't assume you can modify the array elements freely. The operation is locked to a specific type of change. Read the operation definition twice. Map out what it means on a small example before you code. Most wrong submissions come from implementing a different operation than the one the problem defines.
Is this problem still asked at companies after it went public?+
American Express has reported asking it. With an 85% pass rate, it's not a filter question anymore, but it still appears in online assessments. It's a safe problem to prep: if you see it live, you're likely to solve it. If you blank on the operation detail, you have a fallback.
How does Array and Bit Manipulation combine here instead of being separate topics?+
You iterate the array once, maintaining a running XOR value. The Array part is the linear scan. The Bit Manipulation part is the XOR accumulation and the counting of bit differences between current and target XOR. They're inseparable in the solution.
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