Microsoft SDE Interview Experience｜Full Process Review + System Design Answer Analysis

Recent interviews Microsoft SDE The number of students who have applied for Microsoft is particularly high, especially in the recent wave. Many people say that this is the backfill after layoff. For OPT students who still have one year left, it's already a great fortune for Microsoft to appear in the shortlist. I've interviewed with five or six Microsoft groups in a row in the past two weeks, and I've selected the one with the smoothest pace and typical questions, and I'll write it down for your reference while it's still hot.

Overall Pace & Interview Format

Microsoft's recruiting is very special, it is Team Match + multiple rounds of Tech Round mode. The whole process is usually four rounds of interviews, but the content is not fixed at all, each round may be:

Resume Chat Program;
Write Coding directly;
or midway cut System Design (SD).

That said, you never know which type of exam question you're going to face the next minute.
I thought it was standard coding-only before the interview, but halfway through the first round, the interviewer suddenly said, "Let's do a design question as well." It was a direct addition to the question!

Round 1: Coding + System Design Mixed Round

The interviewer was an Indian big brother, very gentle but fast-paced. First, he asked me to briefly introduce a project on my resume, and after five minutes of chatting, he directly cut into coding.

Coding Title: Balanced String Split

Given a string s consisting of characters 'L' And 'R', split it into the maximum number of balanced substrings.
Return the maximum number of balanced substrings.

importation:"RLRRLLRLRL"
exports:4

This question is on the medium side of easy on LeetCode and examines logical clarity and boundary control.

I'll start by dictating the idea: use a balance The variable tracks the current 'L' And 'R' When balance goes back to 0, it means that there is a balanced segment.

When writing code, the interviewer asks for explanations as you write.

def balancedStringSplit(s).
    count, balance = 0, 0
    for ch in s: balance += 1 if ch == 'L' else -1
        balance += 1 if ch == 'L' else -1
        if balance == 0: count += 1
            count += 1
    return count

I wrote it and ran a test myself:

Input: "RLRRLLRLRL"
Output: 4

The interviewer was very pleased and said it was "clean and readable code".

Then he immediately added:

"Good, now let's move to a small design question."

System Design Subtopic: Design a URL Shortener

This question is a classic old one, but Microsoft interviews put more emphasis on the scalability + storage layer trade-off.
I'll start with the needs:

Inputs a long URL and outputs a short link;
Capable of supporting billions of visits;
Short chains should be uniquely reversible.

Then I drew a simple architecture diagram (dictated):

Frontend → API Gateway → Shortener Service;
The Service internally calls the Hash + ID generator;
Redis + MySQL or DynamoDB for the storage tier;
Hot short links plus CDN caching;
Uniqueness is guaranteed with atomic counter for high concurrency.

The interviewer kept asking follow-up, for example:

"What if two URLs generate the same hash?"
My answer: You can add random salt or use base62 encode to avoid conflicts.

The overall exchange was very smooth, and at the end he said, "I like that you focus on trade-offs."
The first round ended successfully.

Round 2: Pure Coding

This round was a white interviewer, wrote the entire time on CoderPad. The topic was graph traversal + DFS logic.

Coding Title: Reorder Routes to Make All Paths Lead to the City Zero

There are n cities connected by n-1 directed roads.
Reorder the roads so that every city can reach city 0.
Return the minimum number of edges to reverse.

Input:

n = 6
connections = [[0,1],[1,3],[2,3],[4,0],[4,5]]

Output: 3

I explained the thought process first:

This is actually a DFS for undirected graphs;
+1 if each edge is not oriented correctly;
Finally the number of reversals is counted.

The code is as follows:

from collections import defaultdict

def minReorder(n, connections): graph = defaultdict(list)
    graph = defaultdict(list)
    for a, b in connections: graph[a].append((b, 1))
        graph[a].append((b, 1)) # need reverse
        graph[b].append((a, 0)) # correct direction

    visited = set()

    def dfs(node).
        visited.add(node)
        count = 0
        
            if nei not in visited.
                count += rev + dfs(nei)
        return count

    return dfs(0)

I was writing and explaining "why we need to build graphs in both directions", and the interviewer was nodding a lot. The interviewer nodded his head a lot. Finally, after running the test samples, the output was correct, he said:

"Great! Clean logic, I like your explanation."

Round 3: In-depth System Design

This round is more in the direction of architecture, and the interviewer is a Senior Engineer.
The title is:Design an Event Logging System.
Require:

Each log entry contains timestamp;
Ability to search by time zone;
The system should support horizontal scaling.

I used the distributed storage idea to answer:

The front-end accepts the log request → Producer;
Kafka / PubSub do message queues;
Consumer Asynchronous writes to partitioned databases;
The query layer is coupled with time indexing (time-based sharding);
To improve query performance, add secondary index + caching.

The interviewer asks, "What if the query range is too large?"
I answered that it can be processed by partition scan + aggregation pipeline, and mentioned that in practice it will do hot and cold data tiering (hot storage vs cold storage).
He listened and said, "That's exactly how we handle it internally."

Round 4: Resume Behavior + Mini-Coding

The last round was on the soft skill side:

"Tell me about a time you disagreed with your teammate."
"What's the most challenging bug you fixed recently?"

The Coding subtopic is a string processing question (slightly easier) that focuses on communication.

Summary and recommendations

Overall, Microsoft's interview style is very "humanized":

The pace is milder than Google or Meta;
Interviewers value "clear explanations + trade-off thinking";
The content of each round is flexible and needs to be improvised.

Prepare recommendations:

Brush up on LeetCode Medium questions mainly;
System Design To have a standard answer framework (goals, core processes, scalability);
Practice verbalization, especially being able to explain ideas while writing.

Programhelp Assisted Service Sharing

I was able to get through all the rounds thanks to Programhelp's real-time mock and voice assistance.
Having simulated a full Microsoft interview scenario in advance, I was able to get into the swing of things quickly with the Coding section;
When you get stuck in the System Design section, you can also get "framework hints" to keep the logic flowing.

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If you're also preparing for interviews with Microsoft, Meta, Amazon, etc., you can customize your assisting service in advance and it will really be much more efficient.

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