[leetcode 122] Best Time to Buy and Sell Stock II

Quesiton：

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 as many transactions as you like (ie, buy one and sell one share of the stock multiple times). However, you may not engage in multiple transactions at the same time
(ie, you must sell the stock before you buy again).

分析：

知道每天股票的价钱，求可得到的最大利益。

首先要确定购买日期，在之后最高价日期卖掉。

代码如下：

<span style="font-size:14px;">class Solution {
public:
int maxProfit(vector<int>& prices) {
if(prices.size() < 2)
return 0;
int buy;
int pro = 0;
int i;
buy = buyPos(prices,0);
for(i = buy; i < prices.size()-1; ++i){
if(prices[i] > prices[i+1] && i != buy){
pro += (prices[i] - prices[buy]);
buy = buyPos(prices,i+1);
i = buy-1;
}
queding

}
if(i == prices.size()-1){
if(prices[i] > prices[buy])
pro += (prices[i] - prices[buy]);
}
return pro;
}
int buyPos(vector<int>& prices,int start){
int i = start;
while(i != prices.size()-1 && prices[i] >= prices[i+1])
++i;
return i;
}
};</span>