079_最佳买卖股票时机含冷冻期

知识点：动态规划

LeetCode第三百零九题：https://leetcode-cn.com/problems/best-time-to-buy-and-sell-stock-with-cooldown/

语言：GoLang

// dp，状态空间压缩
func maxProfit(prices []int) int {
    length := len(prices)
    if length == 0 {
        return 0
    }

    dp_0, dp_1, dp_pre_2 := 0, -prices[0], 0
    for i := 1; i < length; i++ {
        // 今日的昨日，即明日的前日
        tmp := dp_0
        dp_0 = max(dp_0, dp_1 + prices[i])
        dp_1 = max(dp_1, dp_pre_2 - prices[i])
        dp_pre_2 = tmp
    }
    return dp_0
}




// dp
func maxProfit_(prices []int) int {
    length := len(prices)
    if length == 0 {
        return 0
    }

    dp := make([][2]int, length)
    for i := 0; i < length; i++ {
        dp[i] = [2]int{}
    }

    dp[0][0], dp[0][1] = 0, -prices[0]
    for i := 1; i < length; i++ {
        dp[i][0] = max(dp[i - 1][0], dp[i - 1][1] + prices[i])

        if i == 1 {
            dp[i][1] = max(dp[i - 1][1], -prices[i])
        } else {
            dp[i][1] = max(dp[i - 1][1], dp[i - 2][0] - prices[i])
        }
    }
    return dp[length - 1][0]
}
func max(a, b int) int {
    if a > b {
        return a
    }
    return b
}