## Round 1 - Frontend/Coding ## Problem Build a simplified spreadsheet engine. Cells hold integer literals or formulas referencing other cells. When a cell changes, all dependent cells must recompute. ```javascript class Spreadsheet { constructor() {} set(cell, value) {} // value: integer or formula string like "=A1+B2" get(cell) {} // returns computed integer value } ``` ## Example ``` sheet = new Spreadsheet() sheet.set("A1", 5) sheet.set("B1", 10) sheet.set("C1", "=A1+B1") sheet.get("C1") // -> 15 sheet.set("A1", 20) sheet.get("C1") // -> 30 (auto-updated) sheet.set("D1", "=C1*2") sheet.get("D1") // -> 60 ``` ## Approach (optional) Build a dependency graph. On `set`, parse the formula, update the graph, then topologically sort affected cells and recompute them in order. ## Follow-ups 1. How do you detect and handle circular references like `A1 = "=B1"` and `B1 = "=A1"`? 2. Can you support built-in functions like `SUM(A1:A5)` or `MAX(B1,B3,B5)`? 3. If the spreadsheet has 1M cells and 100K are updated at once, how do you batch recomputation efficiently? 4. How would you persist and restore the sheet state?

InterviewDB Experience

Spreadsheet: Build an In-Memory Spreadsheet with Cell Dependency Resolution

Onsite

Interview Experience

Round 1 - Frontend/Coding Problem Build a simplified spreadsheet engine. Cells hold integer literals or formulas referencing other cells. When a cell changes, all dependent cells must recompute. Example Approach (optional) Build a dependency graph. On set, parse the formula, update the graph, then topologically sort affected cells and recompute them in order. Follow-ups How do you detect and handle circular references like A1 = "=B1" and B1 = "=A1"? Can you support built-in functions like SUM(A1…

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About This Question

This is a candidate experience report from a discord interview during the onsite round.

It covers the following topics: Strings, Frontend, Graph, Coding, Onsite .

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Strings Frontend Graph Coding Onsite

About Discord Interview Reports

This question was reported by a candidate who interviewed at Discord. 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 Discord are the higher-signal extractions to take from this report.

For broader preparation context, the Discord 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 Discord reports consistently are the ones worth investing in; one-off niche problems are not.

During Your Discord 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 Discord 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.