diff --git a/notes/64. 求 1+2+3+...+n.md b/notes/64. 求 1+2+3+...+n.md
index 38d7680b..809524a9 100644
--- a/notes/64. 求 1+2+3+...+n.md	
+++ b/notes/64. 求 1+2+3+...+n.md	
@@ -2,7 +2,7 @@
 
 ## 题目链接
 
-[NowCoder](https://www.nowcoder.com/practice/7a0da8fc483247ff8800059e12d7caf1?tpId=13&tqId=11200&tPage=1&rp=1&ru=/ta/coding-interviews&qru=/ta/coding-interviews/question-ranking&from=cyc_github)
+[Leetcode](https://leetcode.cn/problems/qiu-12n-lcof/)
 
 ## 题目描述
 
@@ -17,9 +17,9 @@
 本题的递归返回条件为 n \<= 0，取非后就是 n \> 0；递归的主体部分为 sum += Sum_Solution(n - 1)，转换为条件语句后就是 (sum += Sum_Solution(n - 1)) \> 0。
 
 ```java
-public int Sum_Solution(int n) {
-    int sum = n;
-    boolean b = (n > 0) && ((sum += Sum_Solution(n - 1)) > 0);
+public int mechanicalAccumulator(int target) {
+    int sum = target;
+    boolean b = (target > 0) && ((sum += mechanicalAccumulator(target - 1)) > 0);
     return sum;
 }
 ```