LeetCode
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).
You may not engage in multiple transactions at the same time (ie, you must sell the stock before you buy again).
Solution: Divide and Conquer, DP
O(n^2) solution is easy came out, we can use O(n) time to get max profit depend on the solution of Best Time to Buy and Sell Stock I. so we can just dived the whole prices array at every point , try to calculate current max profit from left and right and then add them together is what we want. However, there are many repeat calculation when calculate left max profit and right max profit. So we can apply DP to record max profits for each left side and right side. then add them together at each point use one for loop
O(n^2) solution is easy came out, we can use O(n) time to get max profit depend on the solution of Best Time to Buy and Sell Stock I. so we can just dived the whole prices array at every point , try to calculate current max profit from left and right and then add them together is what we want. However, there are many repeat calculation when calculate left max profit and right max profit. So we can apply DP to record max profits for each left side and right side. then add them together at each point use one for loop
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