Best Time to Buy and Sell Stock (#121)
You are given an array prices where prices[i] is the price of a given stock on the i-th 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.
Company Tags: Amazon, Facebook, Microsoft
Core Concept: Array, Two-Pointer, Greedy