LeetCode123

class Solution {

public:

    int maxProfit(vector<int>& prices) {

        int buy1=-100000;

        int sell1=0;

        int buy2=-100000;

        int sell2=0;

        for(int i=0;i<prices.size();i++)

        {

            buy1=max(buy1,-prices[i]);

            sell1=max(sell1,prices[i]+buy1);

            buy2=max(buy2,sell1-prices[i]);

            sell2=max(sell2,prices[i]+buy2);

        }

        return sell2;

    }

};