LeetCode 122 Best Time to Buy and Sell Stock II

2024年6月3日 144次阅读

这个题和Best Time to Buy and Sell Stock 是有关的。先看下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.

If you were only permitted to complete at most one transaction (ie, buy one and sell one share of the stock), design an algorithm to find the maximum profit.

Example 1:

Input: [7, 1, 5, 3, 6, 4]
Output: 5

max. difference = 6-1 = 5 (not 7-1 = 6, as selling price needs to be larger than buying price)

Example 2:

Input: [7, 6, 4, 3, 1]
Output: 0

In this case, no transaction is done, i.e. max profit = 0.

而122题规定了可以多次交易，但是卖之前必须买，买之前必须卖，不能连续买或者连续卖。

这个题开始想复杂了，看了看大神解法用的贪心。举个例子，比如1,4,2,5

如果1买5卖那么利润4，但是中间有一次下跌，因此要1买4卖，利润3，2买5卖利润 3，总利润6.简单说碰见涨就卖碰见跌就不动。

class Solution(object):
    def maxProfit(self, prices):
        """
        :type prices: List[int]
        :rtype: int
        """
        return sum([prices[i+1]-prices[i] for i in range(len(prices)-1) if prices[i+1]>prices[i]])
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