diff --git a/docs/notes/剑指 Offer 题解 - 3~9.md b/docs/notes/剑指 Offer 题解 - 3~9.md
index eb7aaec8..17303fa0 100644
--- a/docs/notes/剑指 Offer 题解 - 3~9.md
+++ b/docs/notes/剑指 Offer 题解 - 3~9.md
@@ -132,7 +132,7 @@ Output:
从后向前遍是为了在改变 P2 所指向的内容时，不会影响到 P1 遍历原来字符串的内容。
-
+
```java
public String replaceSpace(StringBuffer str) {
diff --git a/docs/pics/6980aef0-debe-4b4b-8da5-8b1befbc1408.gif b/docs/pics/6980aef0-debe-4b4b-8da5-8b1befbc1408.gif
new file mode 100644
index 00000000..05704a44
Binary files /dev/null and b/docs/pics/6980aef0-debe-4b4b-8da5-8b1befbc1408.gif differ
diff --git a/notes/pics/6980aef0-debe-4b4b-8da5-8b1befbc1408.gif b/notes/pics/6980aef0-debe-4b4b-8da5-8b1befbc1408.gif
new file mode 100644
index 00000000..05704a44
Binary files /dev/null and b/notes/pics/6980aef0-debe-4b4b-8da5-8b1befbc1408.gif differ
diff --git a/notes/剑指 Offer 题解 - 3~9.md b/notes/剑指 Offer 题解 - 3~9.md
index ce3da44a..5ecf7d6d 100644
--- a/notes/剑指 Offer 题解 - 3~9.md
+++ b/notes/剑指 Offer 题解 - 3~9.md
@@ -132,7 +132,7 @@ Output:
从后向前遍是为了在改变 P2 所指向的内容时，不会影响到 P1 遍历原来字符串的内容。
-
+
```java
public String replaceSpace(StringBuffer str) {
