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What is the output of the XOR-based single number function when the input array contains only one element [7]?

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Bit Manipulation - Single Number (XOR Self-Cancellation)
What is the output of the XOR-based single number function when the input array contains only one element [7]?
A0
B7
CError or exception
D-1
Step-by-Step Solution
Solution:

  1. Step 1: Trace XOR with single element

    0 · 7 = 7

  2. Step 2: Return result

    Since only one element, result is that element itself.

  3. Final Answer:

    Option B -> Option B

  4. Quick Check:

    Single element returns itself [OK]
Quick Trick: XOR with zero returns the number itself [OK]
Common Mistakes:
MISTAKES
  • Assuming empty input causes error
  • Forgetting XOR with zero returns number
Trap Explanation:
PITFALL
  • Some think single element input causes error or zero output.
Interviewer Note:
CONTEXT
  • Tests edge case handling and code trace skills.
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