# @param prices int整型一维数组 
# @return int整型
class Solution:
     def maxProfit(self , prices):# -> int :List[int]
        # write code here
        profit,trade,i=0,0,0
        k=len(prices)-2
        if k <0:
            return 0
        while i<=k:
            trade=max(prices[i+1:])-prices[i]
            profit=max(profit,trade)
            i+=1
        return profit

更新一版，思路和上一版大体一致。都是利用max函数来实现。