From 4fab08d0306d82aef04379ef01b9b08aae65543a Mon Sep 17 00:00:00 2001
From: Terry Liu <102352821+Lozakaka@users.noreply.github.com>
Date: Tue, 6 Jun 2023 19:09:57 -0400
Subject: [PATCH] =?UTF-8?q?=E6=8F=90=E4=BE=9BJAVA=E7=9A=842*2=E6=95=B8?=
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原本的空間優化是直接優化成一維數組，故提供一個2*2數組的版本
---
 problems/0121.买卖股票的最佳时机.md | 25 +++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/problems/0121.买卖股票的最佳时机.md b/problems/0121.买卖股票的最佳时机.md
index 753cb106..794185da 100644
--- a/problems/0121.买卖股票的最佳时机.md
+++ b/problems/0121.买卖股票的最佳时机.md
@@ -243,8 +243,27 @@ class Solution {
     }
 }
 ```
+> 动态规划：版本二(使用二維數組（和卡哥思路一致），下面還有使用一維滾動數組的更優化版本)
 
-> 动态规划：版本二
+```Java
+class Solution {
+    public int maxProfit(int[] prices) {
+        int len = prices.length;
+        int dp[][] = new int[2][2];
+        
+        dp[0][0] = - prices[0];
+        dp[0][1] = 0;
+
+        for (int i = 1; i < len; i++){
+            dp[i % 2][0] = Math.max(dp[(i - 1) % 2][0], - prices[i]);
+            dp[i % 2][1] = Math.max(dp[(i - 1) % 2][1], prices[i] + dp[(i - 1) % 2][0]);
+        }
+        return dp[(len - 1) % 2][1];
+    }
+}
+```
+
+> 动态规划：版本二(使用一維數組)
 
 ``` java
 class Solution {
@@ -271,6 +290,10 @@ class Solution {
   }
 }
 ```
+```Java
+
+```
+
 
 Python: