#
# 
# @param prices int整型一维数组 
# @return int整型
#
class Solution:
    def maxProfit(self , prices ):
        # write code here
        profit = 0
        hold = 0
        flag = 0
        for i in range(len(prices)-1):
            if prices[i] < prices[i+1] and not flag:
                flag = 1
                hold = prices[i]
            if prices[i] > prices[i+1] and flag:
                flag = 0
                profit += prices[i] - hold
        if flag:
                profit += prices[len(prices)-1] - hold
        return profit