121-买卖股票的最佳时机.py

class Solution:
    def maxProfit(self, prices: List[int]) -> int:
        if not prices:
            return 0

        dp = [[0, -prices[0]] for i in range(len(prices))]
        for i in range(1, len(prices)):
            dp[i][0] = max(dp[i - 1][0], dp[i - 1][1] + prices[i])
            dp[i][1] = max(dp[i - 1][1], -prices[i])

        return dp[-1][0]