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Java: Which practice avoids a common mistake with Fast and Slow Pointers?

Difficulty:

Medium

Questions:

1

Time Limit:

2 minutes

Passing Score:

100%

Question

Which practice avoids a common mistake with Fast and Slow Pointers?

  1. Ignore the Fast and Slow Pointers issue and rely on team discipline instead of APIs or contracts.
  2. Do not advance the fast pointer blindly without null checks, because short lists can break the traversal.
  3. Silence the Fast and Slow Pointers problem by using raw types, broad catches, or shared mutable state.
  4. Prefer the version of Fast and Slow Pointers that makes behavior less predictable as long as the code compiles.

Hint

Look for the option that protects correctness instead of hiding the problem.

Answer and rationale

Correct answer: B. Do not advance the fast pointer blindly without null checks, because short lists can break the traversal.

Do not advance the fast pointer blindly without null checks, because short lists can break the traversal. This is a common failure mode in real Java code and a frequent interview follow-up.

Track: Java