Leetcode-122 Best Time to Buy and Sell Stock II

最新推荐文章于 2022-07-29 20:36:59 发布

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本文介绍了一种算法，用于计算给定股票价格数组的最大利润。允许进行多次买入卖出操作，但每次卖出后才能再次购买。通过遍历价格数组并计算相邻两天的价格差来实现。

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.

方法一：

首先要证明找到一个gap就要买卖。

然后得到这个问题是找gap。

再简化问题到，只要有大的就做减法。（已经最快了！）

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