Bit Manipulation - Power of Two
Suppose you want to check if a number is a power of two but the input can be a floating-point number. Which approach would you use?
Suppose you want to check if a number is a power of two but the input can be a floating-point number. Which approach would you use?
hard🎤 Interviewer Follow-up Q10 of Q15
Step-by-Step Solution
Solution:
Step 1: Understand floating-point input
Bitwise operations require integers; casting floats may lose precision or be invalid.Step 2: Use logarithm base 2 with tolerance
Checking if log2(n) is close to an integer within a small epsilon accounts for floating-point precision issues.Step 3: Avoid direct equality checks
Direct equality checks on floating-point results are unreliable; tolerance-based checks are standard.Final Answer:
Option A -> Option AQuick Check:
Tolerance-based log2 check is standard for floating-point power of two checks [OK]
Quick Trick: Use log2 with tolerance to check integer result for floats [OK]
Common Mistakes:
MISTAKES- Casting float to int blindly
- Using bitwise ops on floats
- Checking exact equality on log2
Trap Explanation:
PITFALL- Candidates often try bitwise ops on floats or rely on exact equality checks with log2.
Interviewer Note:
CONTEXT- Tests ability to adapt power of two checks to floating-point inputs.
Master "Power of Two" in Bit Manipulation
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