# 122. Best Time to Buy and Sell Stock II

#### Medium

***

You are given an integer array `prices` where `prices[i]` is the price of a given stock on the `ith` day.

On each day, you may decide to buy and/or sell the stock. You can only hold **at most one** share of the stock at any time. However, you can buy it then immediately sell it on the **same day**.

Find and return *the **maximum** profit you can achieve*.

 

**Example 1:**

```
Input: prices = [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.
Total profit is 4 + 3 = 7.
```

**Example 2:**

```
Input: prices = [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.
Total profit is 4.
```

**Example 3:**

```
Input: prices = [7,6,4,3,1]
Output: 0
Explanation: There is no way to make a positive profit, so we never buy the stock to achieve the maximum profit of 0.
```

 

**Constraints:**

* `1 <= prices.length <= 3 * 104`
* `0 <= prices[i] <= 104`

```python
class Solution:
    def maxProfit(self, prices: List[int]) -> int:
        diff = [0]
        for index in range(1, len(prices)):
            diff.append(prices[index] - prices[index-1])
        result = 0
        for _, value in enumerate(diff):
            if value > 0:
                result += value
        return result
```