题解 | #风口的猪-中国牛市# 动态规划

力扣原题官答：

https://leetcode.cn/problems/best-time-to-buy-and-sell-stock-iii/solutions/552695/mai-mai-gu-piao-de-zui-jia-shi-ji-iii-by-wrnt/

#include <algorithm>
#include <vector>
class Solution {
  public:
    /**
     * 计算你能获得的最大收益
     *
     * @param prices Prices[i]即第i天的股价
     * @return 整型
     */
    int calculateMax(vector<int> prices) {
        int n = prices.size();
        int buy1 = -prices[0], sell1 = 0;
        int buy2 = -prices[0], sell2 = 0;
        for (int i = 1; i < n; 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;
    }
};

时间复杂度：O(n)，其中 n 是数组 prices 的长度。

空间复杂度：O(1)