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.
Return the maximum profit from one buy before one sell, or 0 if no profit is possible.
Constraints
- Inputs are Python literals matching the function signature.
- Return a deterministic exact-match value.
Examples
Input: ([7,1,5,3,6,4],)
Expected Output: 5
Explanation: Prompt example.
Input: ([7,6,4,3,1],)
Expected Output: 0
Explanation: No profit.
Input: ([1],)
Expected Output: 0
Explanation: Single day.
Hints
- Use deterministic tie-breaking for prompts with multiple valid outputs.
- For design-style APIs, simulate operations with explicit inputs.