# LeetCode123: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).

#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;
}
posted @ 2014-05-27 10:29  mickole  阅读(329)  评论(0编辑  收藏  举报