Best Time to Buy and Sell Stock III


Say you have an array for which the ith element is the price of a given stock on day i.

 Design an algorithm to find the maximum profit. You may complete at most two transactions.

 Note:
You may not engage in multiple transactions at the same time (ie, you must sell the stock before you buy again).

 Solution:

 Similar to Trapping Rain Water problem. First check from left to right to find the maximum profit between the start to the i-th day.

Then check from right to left to find the maximum profit between the i-th day to the end.

Add two arrays and find the maximum profit.

The following code passes LeetCode Online Large Judge.

Note: my code uses 2n extra spaces, which can be further reduced by n. The rightProfit array is not useful, we only need to store two temporary values.

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