Description：
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).
知道股价，可以有多次买卖，必须先买后卖，求最大利润。
贪心，只要股价比买价高就卖出。
public class Solution { public int maxProfit(int[] prices) { int res = 0; for(int i=0; i<prices.length-1; i++) { if(prices[i] < prices[i+1]) { res += prices[i+1] - prices[i]; } } return res; } }