Xai Software Engineer Interview Questions

This post was last edited by Anonymous on 2025-10-02 12:50 This company places great emphasis on coding. Coding 1: A slight variation of LRU, where each item carries a quantity, so when calculating th

## Problem Given the root of a binary tree, a node is "bad" if its value does not lie within the range `[min_val, max_val]` inherited from its ancestors (similar to BST validity). Remove all bad nodes and their subtrees. Return the modified root. ```python class TreeNode: def __init__(self, val=0, left=None, right=None): ... def remove_bad_nodes( root: TreeNode, min_val: int = float('-inf'), max_val: int = float('inf') ) -> TreeNode | None: pass ``` **Example:** ``` Tree: 5 / \ 1 8 / \ 0 3 Range enforced: left child must be < parent, right child must be > parent Node 8 is bad if 8 > 5 is allowed, but 0 < 1 left of 5... walk through your definition. Output: cleaned tree with only valid-range nodes remaining. ``` ## Follow-ups 1. How does the valid range narrow as you traverse left vs. right? 2. What is the time complexity? Can you do this iteratively? 3. If a bad node has valid children, should the children be re-attached? Why or why not? 4. How would you extend this to an N-ary tree where each child has a specific position constraint?

## Problem Design a durable (persistent) cache that survives process restarts, combining in-memory speed with disk-backed durability. ## Likely LeetCode equivalent No confident LC match. ## Tags hash_table, design, xai, cache

## Problem Build a `DynamicBatcher` that collects incoming requests and flushes them as a batch either when the batch reaches `max_size` items or after `max_wait_ms` milliseconds since the first request in the batch arrived — whichever comes first. ```python class DynamicBatcher: def __init__(self, max_size: int, max_wait_ms: int, process_batch: Callable[[list], list]): ... def submit(self, request: dict) -> Future: """ Returns a Future that resolves when the batch containing this request has been processed. """ ``` **Example behavior:** ``` batcher = DynamicBatcher(max_size=10, max_wait_ms=50, process_batch=db_bulk_insert) f1 = batcher.submit({"id": 1, "data": "..."}) f2 = batcher.submit({"id": 2, "data": "..."}) # If 8 more arrive within 50ms -> all 10 flushed together # If timeout hits first -> flush whatever is pending ``` ## Follow-ups 1. How do you associate each request's Future with its position in the batch result list? 2. What threading model do you use — a background flusher thread, asyncio, or something else? 3. How do you handle partial batch failures where some items succeed and others fail? 4. If the process_batch function is slow and requests pile up, how do you add backpressure?

## Problem Design a real-time audio broadcasting system (similar to Twitter Spaces) handling large concurrent audiences. ## Likely LeetCode equivalent No LC equivalent; system design question. ## Tags system_design, xai, real_time, audio

## Problem: Implement Two Distributed Matrix Multiplication Strategies (DP and FSDP) Using a Communication Simulator You need to implement distributed matrix multiplication **C = A @ B** in a simulat

## Problem: Design a Restorable (Checkpointable) Iterator Design an iterator wrapper `RestorableIterator` that wraps an existing iterator (or an array/list). In addition to normal iteration via `next

## Token Limiter (Rate limiting / quota) Implement a **Token Limiter** component that limits token (quota) consumption for a subject (e.g., userId / apiKey / tenant) under a given rule set. > Note:

## Problem: Unflatten a Nested Template Structure Given a flat list of integers and a nested template structure, refill the template’s leaf integer positions in order to produce a new object with the

## Problem: Flatten a Nested Structure When working with hierarchical data, you may need to convert a nested structure into a flat list. ### Input Given a nested Python-like data structure `structur

Conduct research and machine learning coding

On the Codesignal platform, there are 7 prompts including frontend, backend, and machine learning among others. Choose based on your expertise. Complete the code task as per the prompt and ensure your

Find the kth largest element in a data stream. Implement stream processing to handle the kth largest element in each time window of a large data stream. Use a queue to manage the time window and bucke

Handwrite a parallelized sort algorithm. ### Sample Input ``` 32 12 45 78 23 56 2 98 65 ``` ### Sample Output ``` 2 12 23 32 45 56 65 78 98 ``` ### Test Cases **Case 1** Input: ``` 32 12 45 78 23

Design a rate limiter to control request flow. Limit the frequency of requests within a given time window. ### Sample Input ``` max_requests=10\ntime_window=60 ``` ### Sample Output ``` true\ntrue\n

Design a key-value store system. It should support basic add, delete, and find operations while considering performance. ### Sample Input ``` add key1 value1\nfind key1\ndelete key1\nfind key1\n ```

Given an integer array, sort it. You are required to use multithreading to complete the sorting. ### Sample Input ``` 8 4 10 3 6 9 ``` ### Sample Output ``` 3 4 6 8 9 10 ``` ### Test Cases **Case

Implement an in-memory database task with multiple levels of features. The database supports records identified by string keys, each containing multiple string field-value pairs. ### Level 1 - Basic

Given a list of integers that represent the capacity of rice bags, design an algorithm to determine how to select bags such that their total capacity exceeds a given target. Output the sequence of sel

You need to build a Twitter Insight platform that extracts data from the Twitter API and provides insights. The task includes the following features: 1. Implement a feature that retrieves tweets rela