TikTok interview questions

Block Placement Queries

Support inserting obstacles at points on the nonnegative number line and, for each query, determine whether there exists any obstacle-free interval of length >= sz…

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Array · Binary Indexed Tree · Binary Search · Ordered Set

Cheapest Flights Within K Stops

Find the minimum-cost route from src to dst in a directed weighted graph with the constraint of at most k stops (i.e., a bound on…

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Breadth-First Search · Depth-First Search · Dynamic Programming · Graph Theory

Choose linear regression or decision tree appropriately

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Common coding questions from Leetcode

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Compare bagging vs boosting on imbalanced data

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Compare Random Forests and Boosted Trees: Bias, Variance, Speed

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Supervised Learning

Contrast LSTM and Transformer for long sequences

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Count Number of Nice Subarrays

Count the number of contiguous subarrays that contain exactly k odd numbers in an integer array. The core challenge is to do this in linear…

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Array · Hash Table · Math · Prefix Sum

Course Schedule

Given courses as nodes and prerequisite pairs as directed edges, determine whether the directed graph is acyclic — return true if a topological ordering exists…

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Breadth-First Search · Depth-First Search · Directed Acyclic Graph · Graph Theory

Decode String

Decode a string containing nested repeat patterns of the form k[encoded_string], expanding each bracketed segment k times (k may be multi-digit) possibly with multiple nesting…

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Recursion · Stack · String

Design a URL shortener system like TinyURL

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Design an ad-selection system across objectives

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Design multimodal deployment under compute limits

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Fine-Tuning & Alignment Techniques · MLOps & Model Serving

Design Real-Time Credit Card Fraud Detection System

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ML System Design · Supervised Learning

Design recommendations objective balancing growth and monetization

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Detect and suppress bad sellers robustly

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detect palindrome leetcode question in python

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difference between http and https

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DSA question: container with most water (super easy)

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Estimate heterogeneous treatment effects with causal ML

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Explain and tune XGBoost; prevent overfitting

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Explain FlashAttention, KV cache, and RoPE

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LLM Inference & Serving · Transformers & Attention