adding merge two sorted list

Author: daiyongg-kim

merge-two-sorted-lists/daiyongg-kim.py

@@ -0,0 +1,38 @@
+# Definition for singly-linked list.
+# class ListNode:
+#     def __init__(self, val=0, next=None):
+#         self.val = val
+#         self.next = next
+class Solution:
+    def mergeTwoLists(self, list1: Optional[ListNode], list2: Optional[ListNode]) -> Optional[ListNode]:
+        if list1 is None:
+            return list2
+        if list2 is None:
+            return list1
+        
+        if list1.val < list2.val:
+            list1.next = self.mergeTwoLists(list1.next, list2)
+            return list1
+        else: 
+            list2.next = self.mergeTwoLists(list1, list2.next)
+            return list2
+
+# class Solution:
+#     def mergeTwoLists(self, list1: Optional[ListNode], list2: Optional[ListNode]) -> Optional[ListNode]:
+#         result = ListNode(-1)
+#         dummy = result
+#         while list1 and list2:
+#             if list1.val < list2.val:
+#                 dummy.next = list1
+#                 list1 = list1.next
+#             else:
+#                 dummy.next = list2
+#                 list2 = list2.next
+#             dummy = dummy.next
+        
+#         if list1:
+#             dummy.next = list1
+#         else:
+#             dummy.next = list2
+    
+#         return result.next