Leetcode122-Best Time to Buy and Sell Stock II-Easy

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 (i.e., buy one and sell one share of the stock multiple times).

Note: You may not engage in multiple transactions at the same time (i.e., you must sell the stock before you buy again).

Example 1:

Input: [7,1,5,3,6,4]
Output: 7
Explanation: Buy on day 2 (price = 1) and sell on day 3 (price = 5), profit = 5-1 = 4.
             Then buy on day 4 (price = 3) and sell on day 5 (price = 6), profit = 6-3 = 3.

思路：

 

如果可以交易多次，求利润最大，那么，只要第二天比前一天价格高就卖出。没一个value -> peak 都是一次盈利。

注意：

for循环 i < prices.length -1  注意要-1！因为比较的是 prices[i+1]. 如果i < prices.length, 会出现outOfIndex错误。

 

代码：

class Solution {
    public int maxProfit(int[] prices) {
       int maxProfit = 0;
        
       for (int i = 0; i < prices.length - 1; i++) {
           if (prices[i+1] > prices[i]) {
               maxProfit += prices[i+1] - prices[i];
           }          
        }
        return maxProfit;
    }
}