diff --git a/src/main/java/com/cool/hot100/matrix/Num48.java b/src/main/java/com/cool/hot100/matrix/Num48.java
new file mode 100644
index 0000000..e1bfe9b
--- /dev/null
+++ b/src/main/java/com/cool/hot100/matrix/Num48.java
@@ -0,0 +1,36 @@
+package com.cool.hot100.matrix;
+
+/**
+ * Created with IntelliJ IDEA.
+ *
+ * @Author: Cool
+ * @Date: 2024/09/08/0:03
+ * DayNumber 2
+ * Hard 2
+ * Level 5
+ */
+public class Num48 {
+
+    public void rotate(int[][] matrix) {
+        int len = matrix.length;
+        if (len==0) {
+            return;
+        }
+        int temp;
+        int level = 0; // 层级
+        int maxLevel = len / 2;
+        // 第n行去第len-1-i列
+        //第n列去第n行
+        while (level < maxLevel) {
+            for(int i=level;i<len-level-1;i++){
+                temp=matrix[level][i];
+                matrix[level][i]=matrix[len-1-i][level];
+                matrix[len-1-i][level]=matrix[len-1-level][len-1-i];
+                matrix[len-1-level][len-1-i]=matrix[i][len-1-level];
+                matrix[i][len-1-level]=temp;
+            }
+            level++;
+        }
+    }
+
+}