Best Time to Buy and Sell Stock
You are given an array prices where prices[i] is the price of a given stock on the ith day.
You want to maximize your profit by choosing a single day to buy one stock and a different future day to sell that stock.
Return the maximum profit you can achieve.
If no profit can be made, return 0.
Example 1
Input
6 7 1 5 3 6 4
Output
5
Explanation
Buy on day 2 at price 1 and sell on day 5 at price 6.
Profit = 6 − 1 = 5, which is the maximum possible.
Example 2
Input
5 7 6 4 3 1
Output
0
Explanation
The stock price decreases every day, so no profitable transaction is possible.
Return 0.
Constraints
Hints:
Hint 1
Keep track of the minimum stock price seen so far while traversing the array.
Hint 2
At each day, calculate the profit by selling on that day. Update the maximum profit whenever you find a better one.
Author & Technical Reviewer
Technically reviewed by: ExamAdda Technical Review Team
Technical Reviewers, ExamAdda
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Published
Aug 1, 2026
Last updated
Aug 1, 2026
Content Verification Methodology
Definitions and complexity claims were checked against authoritative computer-science references. Code examples were compiled and tested with standard, boundary and edge-case inputs.
Expected Output