LeetCode123:Best Time to Buy and Sell Stock III

#include <iostream>
#include <vector>
using namespace std;

/**
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) {
        if(prices.empty())
            return 0;
        int n = prices.size();
        int *l = new int[n];
        int *r = new int[n];
        l[0] = 0;
        int lmin = prices[0];
        for(int i = 1; i < n; i++)
        {
            lmin = min(prices[i],lmin);
            l[i] = max(l[i-1], prices[i] - lmin);
        }
        
        r[n-1] = 0;
        int rmax = prices[n-1];
        for(int i = n - 2; i >= 0; i--)
        {
            rmax = max(rmax, prices[i]);
            r[i] = max(r[i+1], rmax - prices[i]);
        }
        
        int maxprofit = 0;
        for(int i = 0; i < n; i++)
        {
            maxprofit = max(maxprofit, l[i] + r[i]);
        }
        delete l;
        delete r;
        return maxprofit;
        
    }
};

int main(void)
{
    int arr[] = {2,4,5,1,7,10};
    int n = sizeof(arr) / sizeof(arr[0]);
    vector<int> stock(arr, arr+n);
    Solution solution;
    int max = solution.maxProfit(stock);
    cout<<max<<endl;
    return 0;
}