Jun 28, 2023 · Jun 8, 2023 · Jun 9, 2023 · Jun 9, 2023 · Jun 28, 2023 · Jun 28, 2023
diff --git a/problems/0309.最佳买卖股票时机含冷冻期.md b/problems/0309.最佳买卖股票时机含冷冻期.md
Original file line number	Diff line number	Diff line change
Expand Up		@@ -200,7 +200,33 @@ class Solution {
		}
		}
		```

	```java
	//using 2*4 array for space optimization
	//這裡稍微說一下,我在LeetCode提交的時候,2*4 2-D array的performance基本上和下面的1-D array performance差不多
	//都是time: 1ms, space: 40.X MB (其實 length*4 的 2-D array也僅僅是space:41.X MB,看起來不多)
	//股票累的DP題目大致上都是這樣,就當作是一個延伸就好了。真的有人問如何優化,最起碼有東西可以講。
	class Solution {
	/**
	1. [i][0] holding the stock
	2. [i][1] after cooldown but stil not buing the stock
	3. [i][2] selling the stock
	4. [i][3] cooldown
	*/
	public int maxProfit(int[] prices) {
	int len = prices.length;
	int dp[][] = new int [2][4];
	dp[0][0] = -prices[0];

	for(int i = 1; i < len; i++){
	dp[i % 2][0] = Math.max(Math.max(dp[(i - 1) % 2][0], dp[(i - 1) % 2][1] - prices[i]), dp[(i - 1) % 2][3] - prices[i]);
	dp[i % 2][1] = Math.max(dp[(i - 1) % 2][1], dp[(i - 1) % 2][3]);
	dp[i % 2][2] = dp[(i - 1) % 2][0] + prices[i];
	dp[i % 2][3] = dp[(i - 1) % 2][2];
	}
	return Math.max(Math.max(dp[(len - 1) % 2][1], dp[(len - 1) % 2][2]), dp[(len - 1) % 2][3]);
	}
	}
	```
		```java
		// 一维数组优化
		class Solution {
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