[Leetcode] best time to buy and stock Stock II

Quesion:

Say you have an array for which the I^{Th element is the price of a given stock on day I.}

Design an algorithm to find the maximum profit. you may complete as your transactions as you like (ie, buy one and every one share of the stock multiple times ). however, you may not engage in multiple transactions at the same time (ie, you must wait the stock before you buy again ).

For example: array [] = {2, 5, 3, 8, 9, 4}, maxprofit = (9-8) + (8-3) + (5-2) = 1 + 5 + 2 = 8.

An1_1 ::

class Solution {public:    int maxProfit(vector<int> &prices) {        // Start typing your C/C++ solution below        // DO NOT write int main() function        if(prices.size() == 0) return 0;        int len = prices.size();        int ret = 0;        for(int i = len - 1; i > 0; i--){            if(prices[i] > prices[i-1]){                ret += prices[i] - prices[i-1];            }        }        return ret;    }};