add new line and time complexity

Author: JisuuungKim

two-sum/JisuuungKim.py

@@ -7,4 +7,6 @@ def twoSum(self, nums: List[int], target: int) -> List[int]:
             if x in d:
                 return [i, d[x]]
             else:
-                d[cur] = i
+                d[cur] = i
+
+    # 시간복잡도 O(n)