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).
输入一组数，代表每日股价。可以多次买入、卖出，每次必须全仓操作。计算最大收益。
思路：当日比前一日上涨时卖出（累加收益）；下跌或持平时买入（不累加收益）。
int maxProfit(vector<int>& prices) {
if(prices.size()==0)return 0;
int sum=0;
for (int i=0;i<prices.size()-1;i++)
{
if(prices[i+1]>prices[i])
sum+=prices[i+1]-prices[i];
}
return sum;
}
