- LeetCode 10 – Regular Expression Matching
The first genuinely Hard problem on the list, and the difficulty is not the code. '*' is not a character — it is a modifier on the character to its left, so x* is one indivisible unit with two branches you must both try. The recursion, why it is exponential, the memo that needs Boolean rather than boolean, the bottom-up table, and the first row that is not all false.
- LeetCode 9 – Palindrome Number
Trivial with toString, which is why the follow-up — solve it without converting to a string — is the real question. Reversing only half the number cannot overflow, unlike reversing all of it. The loop that stops at the midpoint, the odd-digit case that needs reversed / 10, and the trailing-zero guard that makes 10 return false instead of true.
- Load Balancing and the Stateless Tier
Getting a request to a server that can answer it — and, better, not sending it at all. Layer 4 versus layer 7, round robin against least connections, health checks that actually detect a sick instance, and why sticky sessions are a trap rather than a feature. What "stateless" really requires of your application, how a JWT delivers it, and where a CDN removes the request entirely.
- LeetCode 8 – String to Integer (atoi)
Almost no algorithm — a specification-reading exercise dressed as a coding problem, asked because sloppy engineers write parsers that eat production data. The rule that catches people is that atoi clamps to INT_MIN/INT_MAX where Reverse Integer returns zero. Four ordered steps, overflow detected before it happens, and the two Python traps: str.isdigit() and unbounded integers.
- Flask – Interview Questions
Introduction If you are preparing for a Python web developer interview, Flask is one of the most commonly tested frameworks. Whether the role involves building microservices, REST APIs, or full web applications, interviewers expect you to demonstrate not just familiarity with Flask’s API, but a…