### 题目

```
Say you have an array for which the ith element is the price of a given stock on day i.
Design an algorithm to find the maximum profit. You may complete as many transactions as you like (i.e., buy one and sell one share of the stock multiple times).
Note: You may not engage in multiple transactions at the same time (i.e., you must sell the stock before you buy again).
Example 1:
Input: [7,1,5,3,6,4]
Output: 7
Explanation: Buy on day 2 (price = 1) and sell on day 3 (price = 5), profit = 5-1 = 4.
Then buy on day 4 (price = 3) and sell on day 5 (price = 6), profit = 6-3 = 3.
Example 2:
Input: [1,2,3,4,5]
Output: 4
Explanation: Buy on day 1 (price = 1) and sell on day 5 (price = 5), profit = 5-1 = 4.
Note that you cannot buy on day 1, buy on day 2 and sell them later, as you are
engaging multiple transactions at the same time. You must sell before buying again.
Example 3:
Input: [7,6,4,3,1]
Output: 0
Explanation: In this case, no transaction is done, i.e. max profit = 0.
```

现在不管交易的次数了，随便交易多少次都行，但是在买之前必须要把之前已经买的给卖掉。实际上这时候要求最大利润并不难，这时候就相当于只要有得捞就卖掉，虽然不充许同一天进行两次交易，但是因为会抵消，所以和这种的结果是一样的

```
class Solution(object):
def maxProfit(self, prices):
"""
:type prices: List[int]
:rtype: int
"""
if len(prices)<2:
return 0
ret = 0
for i in range(len(prices)-1):
if prices[i+1]>prices[i]: #
ret += prices[i+1]-prices[i]
return ret
```

这个题实际上是个贪心的办法，即只要有钱可以赚就卖掉.