LeetCode:Best Time to Buy and Sell Stock II

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).

思路如下：

找到所有价格的递增区间，每个区间内以对低价买入最高价卖出

 1 class Solution{
 2 public:
 3     int maxProfit(vector<int> &prices){
 4         int len=prices.size();
 5         if(len<=1)
 6         {
 7             return 0;
 8         }
 9         int max=0,i=0;
10         while(i<len-1)
11         {
12             int buy,sell;
13             while(i<len-1&&prices[i+1]<prices[i])i++;
14             buy=i++;
15             while(i<len&&prices[i]>prices[i-1])i++;
16             sell=i-1;
17             max+=prices[sell]-prices[buy];
18         }
19         return max;
20     }
21 };