Solve stock and banana problems
Company: Apple
Role: Machine Learning Engineer
Category: Coding & Algorithms
Difficulty: medium
Interview Round: Onsite
Solve both coding problems below.
1. **Maximum single-transaction stock profit**: Given an array `prices` where `prices[i]` is the stock price on day `i`, return the maximum profit obtainable by choosing one day to buy and a later day to sell. If no profit is possible, return `0`.
2. **Minimum banana-eating speed**: Given an array `piles` where `piles[i]` is the number of bananas in pile `i`, and an integer `h` representing the total number of hours available, find the minimum integer eating speed `k` such that a monkey can finish all piles within `h` hours. In one hour, the monkey chooses one pile and eats up to `k` bananas from that pile.
For each problem, explain your algorithm and analyze time and space complexity.
Quick Answer: This question evaluates algorithmic problem-solving skills related to array processing, optimization under constraints, and reasoning about performance trade-offs by presenting a maximum single-transaction stock profit problem and a minimum banana-eating speed problem.