题目：

题解：

func maxProfit(prices []int) int {buy1, sell1 := -prices[0], 0buy2, sell2 := -prices[0], 0for i := 1; i < len(prices); i++ {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
}func max(a, b int) int {if a > b {return a}return b
}