leetcode122

1. 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).
   数组中放的是当天股票的交易额，可买可卖，但最多只能有一支股票在手～找到一段时间内可获得的最大收益。
   想法就是，遍历交易额的差值，大于零的差值的和就是最大收益啦～也就是只在股票要上涨的时候买入，下降前卖出～

class Solution {public:    int maxProfit(vector<int>& prices) {        int max=0;        int n=prices.size();        if(n<=1)            return 0;        for(int i=0;i<prices.size()-1;i++){            int k=prices[i+1]-prices[i];            if(k>0)                max+=k;        }        return max;    }};