You are given an array, prices, where prices[i] represents the stock price on day $i$.

Determine the maximum profit you can achieve by making at most two transactions. Each transaction consists of a single buy followed by a single sell.

Note: You must complete a sale before initiating a new purchase, and holding multiple stocks at the same time is not allowed.

Constraints:

• $1 \leq$ prices.length $\leq 10^5$ ...