20210822

剑指 Offer 63. 股票的最大利润

class Solution(object):
    def maxProfit(self, prices):
        """
        :type prices: List[int]
        :rtype: int
        """
        #这道题只能买入卖出一次，而不是多次买入卖出
        if not prices:
            return 0
        n = len(prices)
        profits = [0] * n

        #买入
        buy = prices[0]

        for i in range(1,n):

            #price假设是当前卖出的价格
            price = prices[i]
            if price - buy >0:
                profits.append(price-buy)
            else:
                #如果卖出减去买入小于0，将卖出价格赋值给买入价格
                buy = price
        return max(profits)  #最后取出利润最大的值就是最大利润