How do you design a GenAI rebalancing system for Uber that handles multiple driver cancellations in under 10 seconds?

1. Calculate the blast radius and check second-order effects. 2. Use fast spatial indexing (H3) to query nearby drivers. 3. Treat reassignment as a batch matching problem, minimizing total wait time. 4. Recompute ETAs for affected riders using the routing engine. 5. Utilize GenAI for rider communication, not optimization. 6. Budget the 10 seconds across each step. 7. Degrade gracefully if optimal matching isn't possible.