## Problem You are given a street as an array where each element represents a house's property value. Find the length of the longest contiguous subarray of houses where: 1. The difference between the maximum and minimum value in the subarray is at most `k`. 2. The subarray contains at least one house with value >= `threshold`. ```python def longest_valid_block(values: list[int], k: int, threshold: int) -> int: ... ``` **Example:** ``` values = [4, 7, 2, 8, 5, 3], k = 5, threshold = 7 Output: 4 Explanation: Subarray [4,7,2,8] has max=8, min=2, diff=6 > 5. Skip. [7,2,8,5]: max=8,min=2,diff=6. Skip. [4,7,2,8] fails. Try [7,2,8]: diff=6. Hmm. [2,8,5,3]: diff=6. [8,5,3]: diff=5 =7. Length=3. [4,7,2]: diff=5, contains 7>=7. Length=3. Work through to find true max. ``` ## Follow-ups - How do you maintain running max and min efficiently as the window slides? (monotonic deques) - What is the time complexity of your sliding window approach? - Remove condition 2: how does the problem simplify, and does your approach still work?

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Longest Contiguous Houses Matching Criteria - Sliding Window Coding Interview

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Problem You are given a street as an array where each element represents a house's property value. Find the length of the longest contiguous subarray of houses where: The difference between the maximum and minimum value in the subarray is at most k. The subarray contains at least one house with value >= threshold. Example: Follow-ups How do you maintain running max and min efficiently as the window slides? (monotonic deques) What is the time complexity of your sliding window approach? Remove con…

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About This Question

This is a reported interview question from a codesignal interview.

It covers the following topics: Q4, Sliding Window, General Coding Assessment, Coding, Arrays .

Topics

Q4 Sliding Window General Coding Assessment Coding Arrays

About Codesignal Interview Reports

This question was reported by a candidate who interviewed at Codesignal. LeakCode aggregates interview reports from 10+ sources, including 1Point3Acres, Glassdoor, LeetCode Discuss, Blind, Reddit, Indeed, and Nowcoder. Each report is translated where necessary, deduplicated against existing entries, and tagged by company, role, round type, and reporting date.

Use this question as one calibration data point, not a memorization target. Companies typically rotate their question pools every 2-4 months; the exact wording of a 2024 question may differ from what you encounter today. The underlying pattern, difficulty level, and follow-up depth at Codesignal are the higher-signal extractions to take from this report.

For broader preparation context, the Codesignal interview process typically includes a recruiter screen, one or two technical phone screens, and a 4-5 round on-site loop covering coding, system design (at L4+ levels), and behavioral. Reports tagged on LeakCode show the round-by-round distribution and typical difficulty calibration. To browse questions filtered by round type and seniority, use the company hub linked above.

How To Practice This Type of Question

Solve similar problems on LeetCode under timed conditions (25-35 minutes per medium difficulty). The goal is pattern recognition: recognize the underlying technique (sliding window, two-pointer, BFS, memoized recursion, etc.) within 60-90 seconds of reading. Strong candidates verbalize their hypothesis out loud before coding, then iterate based on feedback. Weak candidates dive into implementation immediately, lose time on the wrong approach, and run out of time for follow-ups.

Companies update their question pools every 2-4 months. The exact wording of any given question may have been retired by the time you interview. Focus your prep on the pattern, not the specific problem. The patterns that appear in Codesignal reports consistently are the ones worth investing in; one-off niche problems are not.

During Your Codesignal Round

Apply the standard interview round template: clarify requirements (2-3 minutes), state your approach out loud and confirm direction with the interviewer (3-5 minutes), code with narration (15-25 minutes), test with concrete examples including edge cases (5 minutes), discuss optimization or trade-offs if time permits (5 minutes). This template is universally accepted across FAANG and adjacent companies; deviating from it produces weaker interviewer feedback signal.

The single most predictive failure mode in Codesignal reports tagged "no hire": not asking clarifying questions. Interviewers are explicitly trained to weight this. Strong candidates ask 3-5 clarifying questions even on problems that look obvious; weak candidates dive into code immediately. The clarifying-question check is often the first signal recorded in the interviewer's written notes.