perplexity software engineer tech phone screen: implement ai todo list in python
Interview Experience
Implement ToDo list for AI，Python，给三个 class：TaskStatus（Enum）、Task、ToDoList。4 个 part，每个 part 有 test case。
Part 1 基本 CRUD，不难，抓紧时间。
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Part 2 加 dependency。坑在于要同时 track parent 和 children，一开始只 track 了 children 就得回头改。cascade 逻辑不难理解：变 SUCCEEDED 就 check 依赖它的能不能从 BLOCKED 变 READY，变 FAILED 就递归往下 propagate。DFS 写完了，最后大
test case TLE，没时间修。
面试官没寒暄，上来就让做题，估计他们也知道大部分人做不完吧。第二天拒。
临场发挥真的太难了。
Full Details
Implement ToDo list for AI，Python，给三个 class：TaskStatus（Enum）、Task、ToDoList。4 个 part，每个 part 有 test case。
Part 1 基本 CRUD，不难，抓紧时间。
以下内容需要积分高于 150 您已经可以浏览
Part 2 加 dependency。坑在于要同时 track parent 和 children，一开始只 track 了 children 就得回头改。cascade 逻辑不难理解：变 SUCCEEDED 就 check 依赖它的能不能从 BLOCKED 变 READY，变 FAILED 就递归往下 propagate。DFS 写完了，最后大
test case TLE，没时间修。
面试官没寒暄，上来就让做题，估计他们也知道大部分人做不完吧。第二天拒。
临场发挥真的太难了。
About This Question
This is a candidate experience report from a perplexity interview for a swe role (newgrad level) during the phone screen round reported in 2026.
It covers the following topics: Graph .
Topics
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About Perplexity Interview Reports
This question was reported by a candidate who interviewed at Perplexity. 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 Perplexity are the higher-signal extractions to take from this report.
For broader preparation context, the Perplexity 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 Perplexity reports consistently are the ones worth investing in; one-off niche problems are not.
During Your Perplexity 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 Perplexity 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.