Explain RL policy types and modern policy gradients

Company: TikTok

Role: Software Engineer

Category: Machine Learning

Difficulty: medium

Interview Round: Technical Screen

Quick Answer: This question evaluates understanding of reinforcement learning policy types and modern policy-gradient techniques (TRPO, PPO, GAE) alongside attention mechanism variants (linear attention, Group‑Query Attention), testing competency in algorithmic trade-offs, stability, bias–variance dynamics, and efficiency considerations.