[!info] related notes 动态规划 区间 DP 与状态机 DP 买卖股票的最佳时机

买卖股票的最佳时机（含冷冻期）

题目链接：https://leetcode.cn/problems/best-time-to-buy-and-sell-stock-with-cooldown/

状态设计

• hold：今天结束后持股
• sold：今天刚卖出
• rest：今天结束后不持股、今天没有卖出，次日允许买入；可以由昨天卖出后今天休息得到

转移

newHold = max(oldHold, oldRest - price)
newSold = oldHold + price
newRest = max(oldRest, oldSold)

JavaScript

var maxProfit = function(prices) {
    if (prices.length === 0) return 0;
    let hold = -prices[0];
    let sold = -Infinity;
    let rest = 0;

    for (let i = 1; i < prices.length; i++) {
        const prevHold = hold;
        const prevSold = sold;
        const prevRest = rest;

        hold = Math.max(prevHold, prevRest - prices[i]);
        sold = prevHold + prices[i];
        rest = Math.max(prevRest, prevSold);
    }

    return Math.max(sold, rest);
};