Which modification to the optimal algorithm is necessary to correctly validate the stream?
hard🎤 Interviewer Follow-up Q15 of Q15
Bit Manipulation - UTF-8 Validation
Suppose the UTF-8 validation problem is extended to allow the input data array to be a stream where bytes arrive incrementally, and you must validate the stream in real-time without storing the entire input. Which modification to the optimal algorithm is necessary to correctly validate the stream?
AMaintain a continuation byte counter and validate each byte as it arrives, returning False immediately on invalid bytes.
BUse recursion to validate each character once the full character bytes are available.
CBuffer all bytes until a full character is received before validating to handle partial characters.
DReset the continuation byte counter to zero after every 4 bytes to avoid overflow.
Step-by-Step Solution
Step 1: Understand streaming constraints
In a stream, bytes arrive incrementally and must be validated on the fly without full buffering.
Step 2: Adapt the continuation byte counter approach
Maintain the continuation byte counter state across bytes and validate each byte immediately, returning False if invalid.
Step 3: Avoid buffering or recursion
Buffering or recursion delays validation and is not suitable for real-time streaming.
Final Answer:
Option A -> Option A
Quick Check:
Continuation counter with immediate validation fits streaming constraints [OK]
Quick Trick:Maintain state and validate bytes immediately in streaming [OK]
Common Mistakes:
MISTAKES
Buffering entire characters breaks streaming
Resetting counter incorrectly loses state
Trap Explanation:
PITFALL
Buffering or resetting counter seems plausible but breaks real-time validation correctness.
Interviewer Note:
CONTEXT
Tests candidate's ability to adapt algorithms to streaming or incremental input constraints.
Master "UTF-8 Validation" in Bit Manipulation
3 interactive learning modes - each teaches the same concept differently
