?LeetCode刷題實戰(zhàn)123：買賣股票的最佳時機 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 (i.e., you must sell the stock before you buy again).
題意
解題
class?Solution:
????def?maxProfit(self, prices):
????????"""
????????:type prices: List[int]
????????:rtype: int
????????"""
????????if?not?prices:
????????????return?0
????????len_prices = len(prices)
????????buy1, sell1, buy2, sell2 = -prices[0], 0, -prices[0], 0
????????for?i in?range(1, len_prices):
????????????buy1 = max(buy1, -prices[i])
????????????sell1 = max(sell1, buy1 + prices[i])
????????????buy2 = max(buy2, sell1 - prices[i])
????????????sell2 = max(sell2, buy2 + prices[i])
????????return?sell2