SDE - 1

You have 100 closed doors in a row, and you make 100 passes; on each ith pass, you toggle every ith door (open it if closed, close it if open)—after all passes, how many doors are open and which ones?

Given a sorted array of integers, remove the duplicates in-place such that each element appears only once and return the new length. You must not use extra space.

Given a string, return the length of the longest substring without repeating characters.

You are building a messaging app. Design a data structure to store and retrieve the last N messages of a user efficiently, keeping memory usage optimal.
Implement this in Kotlin using an appropriate data structure and explain your choice.

• Explain the Android Activity Lifecycle. How do lifecycle methods like onCreate(), onStart(), onResume(), etc., work? (Learn)
• What happens when the user presses the back button or receives a call?
• What are launch modes in Android, and how do they affect Activity behaviour?
• What is a memory leak in Android? How can you avoid it? How to detect and fix using tools like LeakCanary.

Build a smart to-do list Android app with MVVM where users can add tasks (title, description, priority), view them sorted by priority and time, filter by priority (All, High, Medium, Low), swipe to delete with Undo Snackbar, and ensure real-time updates via ViewModel using LiveData or StateFlow.

• Tell me about a time you received tough technical feedback — how did you respond and what did you change?
• If you're stuck on a problem for hours and your team is unavailable, how would you approach it?