merge two sorted lists solution

Author: devyejin

merge-two-sorted-lists/devyejin.py

@@ -0,0 +1,30 @@
+# Definition for singly-linked list.
+class ListNode:
+    def __init__(self, val=0, next=None):
+        self.val = val
+        self.next = next
+
+
+"""
+time : O(m+n)
+space : O(1)
+"""
+
+
+class Solution:
+    def mergeTwoLists(self, list1: Optional[ListNode], list2: Optional[ListNode]) -> Optional[ListNode]:
+        dummy = ListNode(None)
+
+        node = dummy
+
+        while list1 and list2:
+            if list1.val <= list2.val:
+                node.next = list1
+                list1 = list1.next
+            else:
+                node.next = list2
+                list2 = list2.next
+            node = node.next
+        node.next = list1 or list2
+
+        return dummy.next