leetcode 121 python(動態規劃）

題目要求：
https://leetcode-cn.com/problems/best-time-to-buy-and-sell-stock/

class Solution:
    def maxProfit(self, prices: List[int]) -> int:
        if not prices:
            return 0
        dp = [0] * len(prices)
        for i in range(1, len(prices)):
            if prices[i]>prices[i-1]:
                dp[i] = prices[i] - min(prices[0:i])
            else:
                dp[i] = dp[i-1]
        return max(dp)

這道題用兩層循環會超時。