[Python手撕]买卖股票（交易k次）

class Solution:
    def maxProfit(self, k: int, prices: List[int]) -> int:

        n = len(prices)

        if k >= n // 2:
            res = 0
            for i in range(1, n):
                if prices[i] > prices[i - 1]:
                    res += prices[i] - prices[i - 1]
            return res
        else:
            dp = [[[0, 0] for i in range(k+1)] for j in range(n)]
            for i in range(1, k+1):
                dp[0][i][1] = -prices[0]

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

            return dp[-1][-1][0]