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Best Time to Buy And Sell Stock

Detailed guide and Python implementation for the 'Best Time to Buy And Sell Stock' problem.

Problem Statement

Easy

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 choosing a different day in the future to sell that stock.

Return the maximum profit you can achieve from this transaction. If you cannot achieve any profit, return 0.

Write a function maxProfit(prices: List[int]) -> int.

Constraints
  • 1 <= len(prices) <= 10^5
  • 0 <= prices[i] <= 10^4

Examples

Example 1
Input
prices = [7, 1, 5, 3, 6, 4]
Output
5
Explanation

Buy on day 2 (price = 1) and sell on day 5 (price = 6). Profit = 6 - 1 = 5.

Example 2
Input
prices = [7, 6, 4, 3, 1]
Output
0
Explanation

No profitable transaction is possible since prices only decrease.

Need a Hint?
Consider using Sliding Window-specific data structures like sets or heaps.
Edge Cases to Watch
  • Empty input structures
  • Single element inputs
  • Large numerical bounds

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