Maximize profit from one stock trade
Company: Two Sigma
Role: Data Scientist
Category: Coding & Algorithms
Difficulty: nan
Interview Round: Technical Screen
## Problem
You are given an integer array `prices` where `prices[i]` is the price of a stock on day `i`.
You may complete **at most one transaction**: choose a day to buy one share and a later day to sell that share.
Return the **maximum profit** you can achieve. If no profit is possible, return `0`.
### Input
- `prices`: array of integers, length `n`
### Output
- An integer: maximum achievable profit
### Constraints
- `1 <= n <= 2 * 10^5`
- `0 <= prices[i] <= 10^9`
### Example
- Input: `prices = [7,1,5,3,6,4]`
- Output: `5` (buy at `1`, sell at `6`)
Quick Answer: This question evaluates algorithmic problem-solving skills with emphasis on array processing, numeric optimization, and time/space complexity analysis in the coding & algorithms domain. It is commonly asked to assess practical implementation ability and efficiency trade-offs under input-size constraints, and the level of abstraction is practical application rather than purely conceptual reasoning.