2020-07-09

Author: JiayangWu

309.最佳买卖股票时机含冷冻期/309-最佳买卖股票时机含冷冻期.py

@@ -0,0 +1,23 @@
+class Solution(object):
+    def maxProfit(self, prices):
+        """
+        :type prices: List[int]
+        :rtype: int
+        """
+        #dp[i][k][1/0]表示第i天还可以交易k次手上持有或没持有股票的状态
+        #对于第二题，k = 2
+        #dp[i][k][0] = max(dp[i - 1][k][0], dp[i - 1][k][1] + price[i])
+        #dp[i][k][1] = max(dp[i - 1][k][1], dp[i - 1][k - 1][0] - price[i])
+        #当k = 0时， dp[i][0][1/0] = 0
+        dp = [[0 for _  in range(2)] for _ in range(len(prices))]
+        
+        for i in range(len(prices)):
+            if i == 0:
+                dp[i][0] = 0
+                dp[i][1] = -prices[i]
+            else:
+                dp[i][0] = max(dp[i - 1][0], dp[i - 1][1] + prices[i])
+                dp[i][1] = max(dp[i - 1][1], dp[i - 2][0] - prices[i])
+        
+        # print dp
+        return dp[len(prices) - 1][0] if prices else 0