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
index 2dc1e874..bb8909cd 100644
--- 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
@@ -284,6 +284,24 @@ const maxProfit = (prices) => {
 };
 ```
 
+```javascript
+// 一维数组空间优化
+const maxProfit = (prices) => {
+  const n = prices.length
+  const dp = new Array(4).fill(0)
+  dp[0] = -prices[0]
+  for (let i = 1; i < n; i ++) {
+    const temp = dp[0] // 缓存上一次的状态
+    const temp1 = dp[2]
+    dp[0] = Math.max(dp[0], Math.max(dp[3] - prices[i], dp[1] - prices[i])) // 持有状态
+    dp[1] = Math.max(dp[1], dp[3]) // 今天不操作且不持有股票
+    dp[2] = temp + prices[i] // 今天卖出股票
+    dp[3] = temp1 // 冷冻期
+  }
+  return Math.max(...dp)
+};
+```
+
 
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