leetcode-----123. 买卖股票的最佳时机 III

• 链接：https://leetcode-cn.com/problems/best-time-to-buy-and-sell-stock-iii/

代码

/*
 * @lc app=leetcode.cn id=123 lang=cpp
 *
 * [123] 买卖股票的最佳时机 III
 * 前后缀分解
 */

// @lc code=start
class Solution {
public:
    int maxProfit(vector<int>& prices) {
        int n = prices.size();
        vector<int> f(n + 2);
        for (int i = 1, minp = INT_MAX; i <= n; ++i) {
            f[i] = max(f[i - 1], prices[i - 1] - minp);
            minp = min(minp, prices[i - 1]);
        }
        int ans = 0;
        for (int i = n, maxp = 0; i; i--) {
            ans = max(ans, maxp - prices[i - 1] + f[i - 1]);
            maxp = max(maxp, prices[i - 1]);
        }
        return ans;
    }
};
// @lc code=end