[23] [Time Beats: 98.49%] [Memory Beats: 51.27%] - LeetPush

Author: 0marSalah

23-Merge-k-Sorted-Lists.py

@@ -0,0 +1,36 @@
+# Definition for singly-linked list.
+# class ListNode:
+#     def __init__(self, val=0, next=None):
+#         self.val = val
+#         self.next = next
+class Solution:
+    def mergeKLists(self, lists: List[Optional[ListNode]]) -> Optional[ListNode]:
+        if not lists: return None
+        while len(lists) > 1:
+            m_list = []
+
+            for i in range(0, len(lists), 2):
+                h1 = lists[i]
+                h2 = lists[i + 1] if (i + 1) < len(lists) else None
+                
+                m_list.append(self.mergeTwoLists(h1, h2))
+            lists = m_list
+        return lists[0]
+
+
+    def mergeTwoLists(self, list1: Optional[ListNode], list2: Optional[ListNode]) -> Optional[ListNode]:
+        dummy = ListNode()
+        tail = dummy
+        while list1 and list2:
+            if list1.val < list2.val:
+                tail.next = list1
+                list1 = list1.next
+            else:
+                tail.next = list2
+                list2 = list2.next
+            tail = tail.next
+        if list1:
+            tail.next = list1
+        elif list2:
+            tail.next = list2
+        return dummy.next