diff --git a/maximum-depth-of-binary-tree/kimjunyoung90.java b/maximum-depth-of-binary-tree/kimjunyoung90.java
new file mode 100644
index 0000000000..c1d851676c
--- /dev/null
+++ b/maximum-depth-of-binary-tree/kimjunyoung90.java
@@ -0,0 +1,6 @@
+public class Solution {
+    public int maxDepth(TreeNode root) {
+        if (root == null) return 0;
+        return 1 + Math.max(maxDepth(root.left), maxDepth(root.right));
+    }
+}
diff --git a/merge-two-sorted-lists/kimjunyoung90.java b/merge-two-sorted-lists/kimjunyoung90.java
new file mode 100644
index 0000000000..0e40239a7b
--- /dev/null
+++ b/merge-two-sorted-lists/kimjunyoung90.java
@@ -0,0 +1,17 @@
+public class Solution {
+    public ListNode mergeTwoLists(ListNode list1, ListNode list2) {
+        //1. null 체크
+        if(list1 == null || list2 == null) {
+            return list1 != null ? list1 : list2;
+        }
+        //1. 값 비교
+        if(list1.val < list2.val) {
+            //다음 Node 비교
+            list1.next = mergeTwoLists(list1.next, list2);
+            return list1;
+        } else {
+            list2.next = mergeTwoLists(list1, list2.next);
+            return list2;
+        }
+    }
+}