From 9287b6be6f3dbcae30e3d5e8c636af24b41a3a7c Mon Sep 17 00:00:00 2001
From: Terry Liu <102352821+Lozakaka@users.noreply.github.com>
Date: Tue, 6 Jun 2023 19:25:22 -0400
Subject: [PATCH] =?UTF-8?q?=E6=96=B0=E5=A2=9EJAVA=202*2=E6=95=B8=E7=B5=84?=
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//DP using 2*2 Array (下方還有使用一維滾動數組的更優化版本)
---
 ...股票的最佳时机II（动态规划）.md | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/problems/0122.买卖股票的最佳时机II（动态规划）.md b/problems/0122.买卖股票的最佳时机II（动态规划）.md
index 146c6a4c..70ab8364 100644
--- a/problems/0122.买卖股票的最佳时机II（动态规划）.md
+++ b/problems/0122.买卖股票的最佳时机II（动态规划）.md
@@ -154,7 +154,24 @@ class Solution
     }
 }
 ```
+```java
+//DP using 2*2 Array (下方還有使用一維滾動數組的更優化版本)
+class Solution {
+    public int maxProfit(int[] prices) {
+        int dp[][] = new int [2][2];
+        //dp[i][0]: holding the stock
+        //dp[i][1]: not holding the stock
+        dp[0][0] = - prices[0];
+        dp[0][1] = 0;
 
+        for(int i = 1; i < prices.length; i++){
+            dp[i % 2][0] = Math.max(dp[(i - 1) % 2][0], dp[(i - 1) % 2][1] - prices[i]);
+            dp[i % 2][1] = Math.max(dp[(i - 1) % 2][1], dp[(i - 1) % 2][0] + prices[i]);
+        }
+        return dp[(prices.length - 1) % 2][1];
+    }
+}
+```
 ```java
 // 优化空间
 class Solution {