Question

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

You are given an array prices where prices[i] is the price of a given stock on the ith day.

Find the maximum profit you can achieve. You may complete at most two transactions.

Note: You may not engage in multiple transactions simultaneously (i.e., you must sell the stock before you buy again).

Approach

• Variable iteration
• https://medium.com/algorithms-and-leetcode/best-time-to-buy-sell-stocks-on-leetcode-the-ultimate-guide-ce420259b323

Solution

class Solution {
public:
    int maxProfit(vector<int>& prices) {
        int a,b,c,d;
        a = INT_MIN;
        b = 0;
        c = INT_MIN;
        d = 0;
        int n = prices.size();
        for(int i=0; i<n; i++) {
            a = max(a, -prices[i]);
            b = max(b, a+prices[i]);
            c = max(c, b-prices[i]);
            d = max(d, c+prices[i]);
        }
        return d;
    }
};