diff --git a/problems/0454.四数相加II.md b/problems/0454.四数相加II.md
index 07c3f711..c2a5710f 100644
--- a/problems/0454.四数相加II.md
+++ b/problems/0454.四数相加II.md
@@ -83,6 +83,9 @@ public:
 
 ```
 
+* 时间复杂度: O(n^2)
+* 空间复杂度: O(n^2)，最坏情况下A和B的值各不相同，相加产生的数字个数为 n^2
+