LeetCode 122 Best Time to Buy and Sell Stock II

1.题目

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).

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给定一个数组，每个元素分别代表每天的股票价格，要求可进行多次交易，求得获取的最大利润和。注意：买入必须在卖出之前。
2.分析：
经过分析，该题目不符合动态规划的要求。由于题目提示可以经过多次交易，则可以通过贪心法来做，遍历一边数组，如发现数组中的元素比前一个元素大，则可以计算出差值，加到最终的总利润中。
采用贪心法求解，时间复杂度为O(n)
code:

public class Solution {    public int maxProfit(int[] prices) {        if(prices==null || prices.length<2){            return 0;        }        int curMin=prices[0];        int profit=0;        int len=prices.length;        for(int i=1;i<len;i++){            if(prices[i]<curMin){                curMin=prices[i];            }else if(prices[i]>curMin){                profit+=prices[i]-curMin;                curMin=prices[i];            }        }        return profit;    }}