Best Time to Buy and Sell Stock II

Source

leetcode:122 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

既然能做任意次交易，那么所有低买高卖的点都把握住，获得收益最大。

只要明天的价格比今天的价格高，那么我便今天买进，第二天卖掉，获得收益为 price[i+1] - price[i]。

那如果连续两天价格上涨呢？第二天，我就不能卖了。但是这两天价格上涨的收益，我都能 得到，只要我今天买进，第三天卖掉即可。

Java 代码

public class Solution {
    public int maxProfit(int[] prices) {
        if (prices == null || prices.length == 0)
            return 0;

        int profit = 0;
        for (int i=0; i < prices.length-1; i++) {
            if (prices[i+1] > prices[i])
                profit += prices[i+1]-prices[i]; 
        }

        return profit;
    }
}