CO @coding_interview_preparation
Showing posts older than #1276 · Back to latest
Forwarded from Programming Quiz Channel
What is a race condition and how do you prevent it?
A race condition occurs when multiple threads access and modify shared data concurrently, and the final result depends on the timing of their execution. This can lead to inconsistent or unpredictable behavior.
To prevent race conditions, I typically use synchronization mechanisms such as mutexes, locks, or semaphores to ensure only one thread modifies critical sections at a time. In some cases, I prefer immutable data structures or atomic operations to reduce locking overhead. The choice depends on the performance requirements and contention level.
Forwarded from Programming Quiz Channel
How do you learn a new technology quickly?
My approach is to first understand the core mental model by reading the official documentation rather than jumping straight into tutorials.
Then I build a small end to end project to get hands on familiarity. After that, I study real world production use cases to understand best practices and common pitfalls.
Finally, I try to apply the technology in a meaningful project because I find retention is much higher when learning is tied to real problems.
How would you handle a sudden spike in traffic?
I would approach this in layers. In the short term, I would protect the system using rate limiting and load shedding to prevent total failure.
Next, I would ensure horizontal scaling behind a load balancer so additional instances can absorb the traffic. I would also introduce caching for frequently requested data and consider using a message queue to smooth traffic spikes.
Long term, I would analyze traffic patterns and redesign any bottlenecks to make the system more resilient to bursty workloads.
What happens when you type a URL into the browser?
When a URL is entered, the browser first checks its cache and then performs DNS resolution to translate the domain name into an IP address.
Next, the browser establishes a TCP connection with the server, followed by a TLS handshake if the connection is HTTPS. The browser then sends an HTTP request to the server.
The server processes the request and returns an HTTP response. Finally, the browser parses the HTML, constructs the DOM and CSSOM, executes JavaScript if present, and renders the page to the screen.
Explain how a hash map works internally.
A hash map stores key value pairs by applying a hash function to the key to compute an index in an underlying array. Ideally, the hash function distributes keys uniformly to minimize collisions.
When collisions occur, common strategies include chaining using linked lists or open addressing. Lookups, insertions, and deletions are O(1) on average but can degrade toward O(n) in worst case collision scenarios.
In modern implementations like Java’s HashMap, when collision chains grow beyond a threshold, they may be converted into balanced trees to maintain efficient performance.
Explain a project you are proud of.
I built a booking system that reduced manual processing. I designed the API with Express and optimized database queries with indexing. As a result, average response time dropped from 900 ms to 180 ms and the system handled 3x more concurrent users.
Tell me about a time you disagreed with a teammate.
In a previous project, we disagreed on introducing a new caching layer. I raised concerns about cache invalidation complexity and proposed we measure current latency first. We ran benchmarks together and agreed on a simpler optimization that met our needs.