CISCO SDE interview questions
Interview Experience
I got shortlisted for an interview at CISCO for SDE position and just finished my interview 30 min before wiriting this post. Background- 3+ yoe, Btech ECE First round was a phone...
Full Details
I got shortlisted for an interview at CISCO for SDE position and just finished my interview 30 min before wiriting this post.
Background- 3+ yoe, Btech ECE
First round was a phone screen round with the Hiring manager at Cisco. It was a resume-based deep dive. I was asked to deeply explain about the products I have worked on and the tech stack they use. My familiarity with the job requirement\'s tech and some overview of the team, work-culture and product I interviewd for.
There will be two coding rounds:
1. Purely coding round
2. Coding + design round
I have only appeared for round 1. The interview started with the discussion on my resume and more deep-dive to resume based projects and tech. I was asked some theory questions too, like-
- What is the difference between SSH and TLS.
- Inner join vs Outer join in databases.
- Transactions and its uses in databased (explained ACID properties here).
The coding question I was asked was a Leetcode medium difficulty question. I am posting the question I was asked below-
https://leetcode.com/problems/maximum-subarray/description/
I am moving forward to the second round of interview too. I will update this post later.
[Update]
Round 2 Coding round
This was again a coding round and focussed more on Golang(since its a go dev role) syntax, goroutines, unbuffered and buffered channels, mutex, waitgroups, etc.
was asked to write a Fibonacci program in go using channels and go routines. Was asked a few more resume-based questions as well.
Round 3 Managerial round
Discussions about project, tech stack, daily requirements and role expections.
The feedback was positive, I am waiting to receive an offer.
About This Question
This is a candidate experience report from a cisco interview for a swe role during the phone screen round reported in 2025.
It covers the following topics: Arrays, Sql, Math, Os, Concurrency, Stack .
Difficulty rating: Medium
More Cisco Interview Questions
About Cisco Interview Reports
This question was reported by a candidate who interviewed at Cisco. 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 Cisco are the higher-signal extractions to take from this report.
For broader preparation context, the Cisco 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 Cisco reports consistently are the ones worth investing in; one-off niche problems are not.
During Your Cisco 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 Cisco 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.