Hard

Quiz

#123 Best Time to Buy and Sell Stock III

APPROACH

An array prices is given where prices[i] is the stock price on day i.

Compute the maximum profit achievable with at most two transactions.

Note: You must sell your current holding before making a new purchase.

Example 1:

Input: prices = [3,3,5,0,0,3,1,4]

Output: 6

Explanation: Buy on day 4 (price = 0) and sell on day 6 (price = 3), profit = 3-0 = 3.

Then buy on day 7 (price = 1) and sell on day 8 (price = 4), profit = 4-1 = 3.

Example 2:

Input: prices = [1,2,3,4,5]

Output: 4

Explanation: Buy on day 1 (price = 1) and sell on day 5 (price = 5), profit = 5-1 = 4.

Note that you cannot buy on day 1, buy on day 2 and sell them later, as you are engaging multiple transactions at the same time. You must sell before buying again.

Example 3:

Input: prices = [7,6,4,3,1]

Output: 0

Explanation: In this case, no transaction is done, i.e. max profit = 0.

1 of 4

1:00

What is the optimal approach for this problem?