Solution: Best Time to Buy and Sell Stock

Statement

Given an array, prices, where prices[i] represent the price of a stock on the i-th day, maximize profit by selecting a single day to buy the stock and a different day in the future to sell it.

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

Constraints:

• We can’t sell before buying a stock, that is, the array index at which stock is bought will always be less than the index at which the stock is sold.

• $1$ $\leq$ prices.length $\leq$ $10 ^ 3$ ...