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.
1 <= prices.length <= 10^50 <= prices[i] <= 10^4prices = [7,1,5,3,6,4]5prices = [7,6,4,3,1]0