diff --git a/src/main/java/com/cool/ling_cha_mount/stack/Num1124.java b/src/main/java/com/cool/ling_cha_mount/stack/Num1124.java
new file mode 100644
index 0000000..ee3d258
--- /dev/null
+++ b/src/main/java/com/cool/ling_cha_mount/stack/Num1124.java
@@ -0,0 +1,25 @@
+package com.cool.ling_cha_mount.stack;
+
+import java.util.Deque;
+import java.util.LinkedList;
+
+public class Num1124 {
+    public int longestWPI(int[] hours) {
+        int res = 0;
+        int[] arr = new int[hours.length + 1];
+        Deque<Integer> stack = new LinkedList<>();
+        stack.push(0);
+        for (int i = 1; i <= hours.length; i++) {
+            arr[i] = arr[i - 1] + (hours[i - 1] > 8 ? 1 : -1);
+            if (arr[i] < arr[stack.peek()]) {
+                stack.push(i);
+            }
+        }
+        for (int i = hours.length; i > 0; i--) {
+            while (!stack.isEmpty() && arr[i] > arr[stack.peek()]) {
+                res = Math.max(res, i - stack.pop());
+            }
+        }
+        return res;
+    }
+}