# @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=0,0
        for i in range(len(prices)-1):
            trade=max(prices[i+1:])-prices[i]
            profit=max(profit,trade)
        return profit