diff --git a/src/main/java/com/cool/hot100/substring/Num239.java b/src/main/java/com/cool/hot100/substring/Num239.java
new file mode 100644
index 0000000..9785296
--- /dev/null
+++ b/src/main/java/com/cool/hot100/substring/Num239.java
@@ -0,0 +1,41 @@
+package com.cool.hot100.substring;
+
+import java.util.Deque;
+import java.util.LinkedList;
+
+/**
+ * Created with IntelliJ IDEA.
+ *
+ * @Author: Cool
+ * @Date: 2024/09/05/13:46
+ * DayNumber 2
+ * Hard 3
+ * Level ?
+ */
+public class Num239 {
+
+
+    public int[] maxSlidingWindow(int[] nums, int k) {
+        int[] ans = new int[nums.length - k + 1];
+        Deque<Integer> queue = new LinkedList<>();
+        for (int i = 0; i < k; i++) {
+            while (!queue.isEmpty() && nums[queue.peekLast()] <= nums[i]) {
+                queue.pollLast();
+            }
+            queue.offerLast(i);
+        }
+        ans[0] = nums[queue.peekFirst()];
+        for (int i = k; i < nums.length; i++) {
+            while (!queue.isEmpty() && nums[queue.peekLast()] <= nums[i]) {
+                queue.pollLast();
+            }
+            queue.offerLast(i);
+            while (!queue.isEmpty() && i - queue.peekFirst() >= k) {
+                queue.pollFirst();
+            }
+            ans[i - k + 1] = nums[queue.peekFirst()];
+        }
+        return ans;
+    }
+
+}