Amazon

## Round 1 — DSA + Behavioral ### DSA Recover BST** I was given a Binary Search Tree (BST) in which the values of two nodes had been exchanged. I had to find those two nodes and swap their values back to restore the BST. Edit Distance** I was given two strings `s1` and `s2`. I could perform three operations: Insert a character Remove a character Replace a character I had to return the minimum number of operations required to convert `s1` into `s2`. ### Behavioral Deadline / Prioritization** Tell me about a situation where you had a deadline to complete a task. How did you prioritize your work to make sure you completed it on time? - ## Round 2 — DSA + OS ### DSA / Bit Manipulation I was given an 8-bit memory address and asked to toggle a particular bit in the value stored at that address. The initial approach involved reading the value, toggling the required bit, and writing the updated value back. The follow-up question was: What would you do if the given memory address was write-only and you could not read the value stored at that address?** ### Operating Systems The OS part covered a broad range of topics: Mutex Semaphore Mutex vs Semaphore TLB Virtual Memory Paging Page Tables Page Faults Page Replacement Processes and Threads Context Switching Process States CPU Scheduling Deadlocks Race Conditions Critical Sections Spinlocks Linux basics Linux Processes `fork()`, `exec()`, `wait()` Zombie and Orphan Processes IPC Memory Management Synchronization