Bit Manipulation - Power of Two
Given the output of isPowerOfTwo(218) is False, which of the following inputs would produce True for the same function?
Given the output of isPowerOfTwo(218) is False, which of the following inputs would produce True for the same function?
hard🔄 Reverse Engineer Q9 of Q15
Step-by-Step Solution
Solution:
Step 1: Understand why 218 returns False
218 in binary has multiple set bits, so n & (n - 1) != 0.Step 2: Identify input with single set bit
256 is 2^8, binary 100000000, so n & (n - 1) == 0, returns True.Final Answer:
Option B -> Option BQuick Check:
Only powers of two return True [OK]
Quick Trick: Only powers of two have one set bit [OK]
Common Mistakes:
MISTAKES- Choosing non-power of two numbers
- Ignoring zero and negative inputs
Trap Explanation:
PITFALL- Candidates confuse numbers close to powers of two with actual powers of two.
Interviewer Note:
CONTEXT- Tests reverse reasoning from output to input properties.
Master "Power of Two" in Bit Manipulation
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