'''
Description: 
Autor: Au3C2
Date: 2020-12-23 16:32:34
LastEditors: Au3C2
LastEditTime: 2020-12-23 16:34:02
'''
class Solution:
    def maxProfit(self, prices: List[int]) -> int:
        n = len(prices)
        buy = prices[0]
        profit = 0
        for i in range(1, n):
            if prices[i] < buy:
                buy = prices[i]
            elif prices[i] > buy:
                profit += prices[i] - buy
                buy = prices[i]
        return profit
# 动态规划，简单.👆贪心算法
# 0121.买卖股票的最佳时机的买卖多次版
# https://leetcode-cn.com/problems/best-time-to-buy-and-sell-stock-ii/

👇动态规划

class Solution:
    def maxProfit(self, prices: List[int]) -> int:
        dp0 = 0             # 手里没股票
        dp1 = - prices[0]   # 手里有股票
        for i in range(1, len(prices)):
            dp0 = max(dp0, dp1 + prices[i])
            dp1 = max(dp1, dp0 - prices[i])
        return dp0