Best Time to Buy and Sell Stock III

Say you have an array for which the ith element is the price of a given stock on day i.

Design an algorithm to find the maximum profit. You may complete at most two transactions.

Note:
You may not engage in multiple transactions at the same time (ie, you must sell the stock before you buy again).

class Solution {

public:

    int maxProfit(vector<int> &prices) 

    {

        int n=prices.size();

        int maxpro=profit(prices,0,n-1);

        for(int i=1;i<n-1;i++)

        if(prices[i]>=prices[i-1] && prices[i]>prices[i+1])

        {

            int pro=profit(prices,0,i)+profit(prices,i+1,n-1);

            if(pro>maxpro) maxpro=pro;

        }

        return maxpro;

    }

    int profit(const vector<int>& prices,int l,int r)

    {

        if(l>=r) return 0;

        

        int low=prices[l];

        int maxpro=0;

        for(int i=l+1;i<=r;i++)

        {

            if(prices[i]-low>maxpro)

                maxpro=prices[i]-low;

            if(prices[i]<low) low=prices[i];

        }

        return maxpro;

    }

};