修复990题的超链接

Author: Wei Hu

算法思维系列/UnionFind算法应用.md

@@ -18,7 +18,7 @@
 
 [130.被围绕的区域](https://leetcode-cn.com/problems/surrounded-regions)
 
-[990.等式方程的可满足性](https://leetcode-cn.com/problems/surrounded-regions)
+[990.等式方程的可满足性](https://leetcode-cn.com/problems/satisfiability-of-equality-equations)
 
 **-----------**
 
@@ -250,4 +250,4 @@ boolean equationsPossible(String[] equations) {
 <img src="../pictures/qrcode.jpg" width=200 >
 </p>
 
-======其他语言代码======
+======其他语言代码======