目录

学习目标

学习内容

 123.买卖股票的最佳时机III  

  188.买卖股票的最佳时机IV 

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学习目标

学习内容

 123.买卖股票的最佳时机III  

123. 买卖股票的最佳时机 III - 力扣（LeetCode）https://leetcode.cn/problems/best-time-to-buy-and-sell-stock-iii/

class Solution:
    def maxProfit(self, prices: List[int]) -> int:
        n = len(prices)
        a,b,c,d = -prices[0],0,-prices[0],0
        for i in range(n):
            a = max(a,-prices[i])
            b = max(b,a+prices[i])
            c = max(c,b-prices[i])
            d = max(d,c+prices[i])
        return d

  188.买卖股票的最佳时机IV 

188. 买卖股票的最佳时机 IV - 力扣（LeetCode）https://leetcode.cn/problems/best-time-to-buy-and-sell-stock-iv/

class Solution:
    def maxProfit(self, k: int, prices: List[int]) -> int:
        n = len(prices)
        if k==0:return 0
        dp = [0]*(2*k)
        for i in range(2*k):
            if i%2==0:
                dp[i] = -prices[0]
        for i in range(n):
            for j in range(2*k):
                if j%2==0:
                    if j==0:
                        dp[j] = max(dp[j],-prices[i])
                    else:
                        dp[j] = max(dp[j],dp[j-1]-prices[i])
                else:
                    dp[j] = max(dp[j],dp[j-1]+prices[i])
        return dp[-1]