Best Time To Buy And Sell Stock · Interview Problem

Back to problems

Leetcode

Easy

Arrays

Greedy

Dynamic Programming

Amazon

Microsoft

Best Time To Buy And Sell Stock

Find the maximum profit from one buy and one sell of a stock over a sequence of daily prices.

Acceptance 100%

Start Practice

Problem Statement

Problem

You are given an array prices where prices[i] is the stock price on day i.

You may complete at most one transaction: buy one share on one day and sell that share on a later day.

Return the maximum profit you can achieve. If no profitable transaction exists, return 0.

Notes

You must buy before you sell.
You can only hold one share at a time.
If prices never rise after a buy day, the best action is to do nothing.

Input Format

A single integer array prices.
prices[i] represents the stock price on day i.

Output Format

Return a single integer: the maximum possible profit from one buy/sell transaction.

Constraints

1 <= prices.length
Prices are non-negative integers.
You may make at most one buy and one sell.
The sell day must be strictly after the buy day.

Examples

Sample cases returned by the problem API.

Example 1

Input

prices = [7,1,5,3,6,4]

Output

Explanation

Buy on day 2 at price 1 and sell on day 5 at price 6 for a profit of 5.

Example 2

Input

prices = [7,6,4,3,1]

Output

Explanation

Prices only decrease, so no profitable transaction exists.

Premium problem context

Unlock deeper context for this problem

Premium adds guided hints, editorial links, similar variants, discussion resources, and concept maps so you can understand why a problem matters, not just solve it once.

Guided hints

Editorial and discussion links

Concept map and variants

Track your progress