diff --git a/src/main/java/leet/book/queueStack/MovingAverage.java b/src/main/java/leet/book/queueStack/MovingAverage.java
new file mode 100644
index 0000000..e5b4ddd
--- /dev/null
+++ b/src/main/java/leet/book/queueStack/MovingAverage.java
@@ -0,0 +1,45 @@
+package leet.book.queueStack;
+
+import java.util.LinkedList;
+import java.util.Queue;
+
+/**
+ * Created with IntelliJ IDEA.
+ *
+ * @author: 轩辕龙儿
+ * @date: 2021/7/2 8:44
+ * @Description: No Description
+ */
+public class MovingAverage {
+    Queue<Integer> queue;
+    int size;
+    double sum = 0.0;
+
+    /**
+     * Initialize your data structure here.
+     */
+    public MovingAverage(int size) {
+        queue = new LinkedList<>();
+        this.size = size;
+    }
+
+    public double next(int val) {
+        if (queue.size() >= size) {
+            sum += 1.0 * (val - queue.poll()) / size;
+        } else {
+            if (queue.isEmpty()) {
+                sum += val;
+            } else {
+                sum = (sum * queue.size() + val) / (queue.size() + 1);
+            }
+        }
+        queue.offer(val);
+        return sum;
+    }
+}
+
+/**
+ * Your MovingAverage object will be instantiated and called as such:
+ * MovingAverage obj = new MovingAverage(size);
+ * double param_1 = obj.next(val);
+ */
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