Best time to buy and sell stock

Problem Description

You are given an array prices where prices[i] represents the price of a given stock on the i-th day.

Your goal is to maximize your profit by choosing a single day to buy one stock and a different day in the future to sell that stock.

Return the maximum profit you can achieve from this transaction. If no profit can be made, return 0.

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.
Note that buying on day 2 and selling on day 1 is not allowed because you must buy before you sell.

Example 2

Input:
prices = [7,6,4,3,1]
Output:
0
Explanation:
In this case, no transactions are done and the max profit = 0.

Constraints

• 1 <= prices.length <= 10^5
• 0 <= prices[i] <= 10^4

Code Template

class Solution:
    def maxProfit(self, prices: List[int]) -> int:
        # Write your code here
        pass

Solutions

• Solution 1: This approach uses a brute-force method to check all possible pairs of buy and sell days to find the maximum profit.
• Solution 2: This approach optimizes the process by keeping track of the minimum price seen so far and calculating potential profits in a single pass through the array.

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