add js solution for maxProfit with Cooldown

problems/0309.最佳买卖股票时机含冷冻期.md

@@ -207,7 +207,29 @@ class Solution:
 
 Go：
 
+Javascript:
 
+```javascript
+const maxProfit = (prices) => {
+    if(prices.length < 2) {
+        return 0
+    } else if(prices.length < 3) {
+        return Math.max(0, prices[1] - prices[0]);
+    }
+
+    let dp = Array.from(Array(prices.length), () => Array(4).fill(0));
+    dp[0][0] = 0 - prices[0];
+
+    for(i = 1; i < prices.length; i++) {
+        dp[i][0] = Math.max(dp[i - 1][0], Math.max(dp[i-1][1], dp[i-1][3]) - prices[i]);
+        dp[i][1] = Math.max(dp[i -1][1], dp[i - 1][3]);
+        dp[i][2] = dp[i-1][0] + prices[i];
+        dp[i][3] = dp[i-1][2];
+    }
+
+    return Math.max(dp[prices.length - 1][1], dp[prices.length - 1][2], dp[prices.length - 1][3]);
+};
+```
 
 
 -----------------------