Cloud Engineer • Coding • medium

Given a massive, 100GB web server log file, write a script to find the top K most frequent IP addresses making requests. The script must run on a machine with only 4GB of RAM.

#Log Parsing #Memory Management #Heaps #Hash Maps

Practice

Cloud Engineer • Coding • hard

Implement a thread-safe bounded blocking queue. It should support enqueue and dequeue operations, blocking if the queue is full or empty, respectively.

#Multithreading #Synchronization #Data Structures

Practice

Cloud Engineer • Coding • easy

Write a function to validate if a given string is a valid IPv4 or IPv6 address. Do not use built-in IP validation libraries.

#String Manipulation #Validation #Edge Cases

Practice

Data Engineer • Coding • medium

Write a Python function to merge overlapping user session intervals. Given an array of intervals where intervals[i] = [start_i, end_i], merge all overlapping intervals and return an array of the non-overlapping intervals.

#Arrays #Sorting #Intervals

Practice

Data Engineer • Coding • medium

Given a list of dictionaries representing Facebook post interactions (user_id, post_id, interaction_type, timestamp), write a Python script to return the top 3 most engaged posts for each interaction type.

#Dictionaries #Heaps #Data Aggregation

Practice

Data Engineer • Coding • easy

Given an array of integers representing the number of likes on a user's posts, write a Python function to move all zeros (posts with zero likes) to the end of the array while maintaining the relative order of the non-zero elements. Do this in-place.

#Arrays #Two Pointers #In-place Manipulation

Practice

Data Engineer • Coding • medium

Write a Python script to parse a massive JSONL file (100GB+) containing WhatsApp message metadata. Calculate the total number of messages sent per country code. You cannot load the entire file into memory.

#File I/O #Memory Management #Generators #JSON

Practice

Machine Learning Engineer • Coding • medium

Given two sparse vectors represented as arrays of non-zero elements and their indices, write a function to compute their dot product. Optimize for both time and space complexity.

#Arrays #Hash Table #Two Pointers

Practice

Machine Learning Engineer • Coding • medium

Given a binary tree, write an algorithm to find the lowest common ancestor (LCA) of two given nodes. Assume each node has a pointer to its parent.

#Trees #Pointers #Hash Table

Practice

ML Engineer • Coding • hard

Implement a K-means clustering algorithm from scratch in Python.

#K-Means #Clustering

Practice

ML Engineer • Coding • medium

Implement a sliding window approach to detect anomalies in a time series.

#Anomaly Detection #Time Series

Practice

ML Engineer • Coding • hard

Implement logistic regression with gradient descent in NumPy.

#Logistic Regression #NumPy

Practice

Software Engineer • Coding • medium

Given two nodes p and q in a binary tree representing an organizational chart, return their lowest common ancestor (LCA). Each node has a reference to its parent node, but you do not have a reference to the root.

#Trees #Pointers #Linked Lists

Practice

Software Engineer • Coding • medium

Given a list of user session intervals [start, end] representing the time a user spent active on the Facebook app, merge all overlapping sessions to return an array of non-overlapping continuous active sessions.

#Sorting #Arrays #Intervals

Practice

Software Engineer • Coding • medium

Given an array of integers representing daily ad click counts and a target integer k, return the total number of continuous days (subarrays) whose sum of clicks equals exactly k.

#Prefix Sum #Hash Table #Arrays

Practice

Software Engineer • Coding • easy

Given a string s representing a user's text input, return true if the string can be a palindrome after deleting at most one character.

#Two Pointers #String Manipulation

Practice

Software Engineer • Coding • medium

Given a string of '(' , ')' and lowercase English characters representing a malformed mathematical expression in a Meta internal tool. Remove the minimum number of parentheses so that the resulting string is valid and return it.

#Stacks #String Manipulation

Practice

Software Engineer • Coding • medium

Given the root of a binary tree representing a hierarchical DOM structure, return the vertical order traversal of its nodes' values (from top to bottom, column by column).

#Breadth-First Search #Hash Table #Binary Trees

Practice

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Interview Question Bank

Given a massive, 100GB web server log file, write a script to find the top K most frequent IP addresses making requests. The script must run on a machine with only 4GB of RAM.

Implement a thread-safe bounded blocking queue. It should support enqueue and dequeue operations, blocking if the queue is full or empty, respectively.

Write a function to validate if a given string is a valid IPv4 or IPv6 address. Do not use built-in IP validation libraries.

Write a Python function to merge overlapping user session intervals. Given an array of intervals where intervals[i] = [start_i, end_i], merge all overlapping intervals and return an array of the non-overlapping intervals.

Given a list of dictionaries representing Facebook post interactions (user_id, post_id, interaction_type, timestamp), write a Python script to return the top 3 most engaged posts for each interaction type.

Given an array of integers representing the number of likes on a user's posts, write a Python function to move all zeros (posts with zero likes) to the end of the array while maintaining the relative order of the non-zero elements. Do this in-place.

Write a Python script to parse a massive JSONL file (100GB+) containing WhatsApp message metadata. Calculate the total number of messages sent per country code. You cannot load the entire file into memory.

Given two sparse vectors represented as arrays of non-zero elements and their indices, write a function to compute their dot product. Optimize for both time and space complexity.

Given a binary tree, write an algorithm to find the lowest common ancestor (LCA) of two given nodes. Assume each node has a pointer to its parent.

Implement a K-means clustering algorithm from scratch in Python.

Implement a sliding window approach to detect anomalies in a time series.

Implement logistic regression with gradient descent in NumPy.

Given two nodes p and q in a binary tree representing an organizational chart, return their lowest common ancestor (LCA). Each node has a reference to its parent node, but you do not have a reference to the root.

Given a list of user session intervals [start, end] representing the time a user spent active on the Facebook app, merge all overlapping sessions to return an array of non-overlapping continuous active sessions.

Given an array of integers representing daily ad click counts and a target integer k, return the total number of continuous days (subarrays) whose sum of clicks equals exactly k.

Given a string s representing a user's text input, return true if the string can be a palindrome after deleting at most one character.

Given a string of '(' , ')' and lowercase English characters representing a malformed mathematical expression in a Meta internal tool. Remove the minimum number of parentheses so that the resulting string is valid and return it.

Given the root of a binary tree representing a hierarchical DOM structure, return the vertical order traversal of its nodes' values (from top to bottom, column by column).

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