代码随想录day50|123. 买卖股票的最佳时机 III188. 买卖股票的最佳时机 IV

123. 买卖股票的最佳时机 III

class Solution:
    def maxProfit(self, prices: List[int]) -> int:
        dp=[[0]*5 for _ in range(len(prices))]
        dp[0][0]=0
        dp[0][1]=-prices[0]
        dp[0][2]=0
        dp[0][3]=-prices[0]
        dp[0][4]=0
        for i in range(1,len(prices)):
            dp[i][0] = dp[i-1][0]
            dp[i][1] = max(dp[i-1][1],dp[i-1][0]-prices[i])
            dp[i][2]=max(dp[i-1][2],dp[i-1][1]+prices[i])
            dp[i][3]=max(dp[i-1][3],dp[i-1][2]-prices[i])
            dp[i][4]=max(dp[i-1][4],dp[i-1][3]+prices[i])
        return dp[len(prices)-1][4]

188. 买卖股票的最佳时机 IV

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