Adobe Coding Question: Shortest Subarray with K Distinct

Problem overview

You are given an integer array nums and an integer k. Implement a function that returns the minimum length of a contiguous subarray that contains exactly k distinct integers. If no such subarray exists, return 0.

What you'll be asked to do

You should describe a linear-time approach using a sliding-window (two-pointer) pattern plus a hash table (frequency map). Walk through expanding the right pointer until your window includes k distinct values, then move the left pointer forward to shrink the window while still keeping exactly k distinct values — updating the minimum length whenever the window contains exactly k distinct integers.

Interview flow / stages

• Clarify edge cases (k == 0, k > number of distinct values in the whole array, empty array).
• Propose the sliding-window + hashmap plan and state time/space complexity.
• Implement carefully, explaining how you maintain counts and when you update the answer.
• Discuss correctness and test on small examples and corner cases.

Skill signals the interviewer is looking for

• Mastery of sliding-window and two-pointer techniques
• Correct use of hash maps to track frequencies and distinct counts
• Ability to reason about edge cases and complexity (aim for O(n) time and O(min(n, alphabet)) space)
• Clear incremental testing and explanation of why the shrink/expand steps maintain correctness

Try writing a clear, bug-free implementation you can walk through on a whiteboard or in a shared editor.