diff --git a/problems/0209.长度最小的子数组.md b/problems/0209.长度最小的子数组.md
index 53e03077..0aaa466e 100644
--- a/problems/0209.长度最小的子数组.md
+++ b/problems/0209.长度最小的子数组.md
@@ -150,19 +150,20 @@ class Solution:
 Java：
 ```java
 class Solution {
-    public int minSubArrayLen(int target, int[] nums) {
-        Integer size = Integer.MAX_VALUE;
-        int from = 0;
-        int to = 0;
+
+    // 滑动窗口
+    public int minSubArrayLen(int s, int[] nums) {
+        int left = 0;
         int sum = 0;
-        while (to < nums.length) {
-            sum += nums[to++];
-            while (sum >= target) {
-                size = Math.min(size,to - from);
-                sum -= nums[from++];
+        int result = Integer.MAX_VALUE;
+        for (int right = 0; right < nums.length; right++) {
+            sum += nums[right];
+            while (sum >= s) {
+                result = Math.min(result, right - left + 1);
+                sum -= nums[left++];
             }
         }
-        return size == Integer.MAX_VALUE ? 0 : size;
+        return result == Integer.MAX_VALUE ? 0 : result;
     }
 }
 ```