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LC_23.py
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LC_23.py
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# 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[ListNode]) -> ListNode:
if not lists or len(lists) == 0:
return None
def merge(l1, l2):
dummy = curr = ListNode(0)
while l1 and l2:
if l1.val <= l2.val:
curr.next = l1
l1 = l1.next
else:
curr.next = l2
l2 = l2.next
curr = curr.next
if l1:
curr.next = l1
if l2:
curr.next = l2
return dummy.next
while (len(lists) > 1):
mergedLists = []
for i in range(0, len(lists), 2):
l1 = lists[i]
l2 = lists[i + 1] if (i + 1) < len(lists) else None
mergedLists.append(merge(l1, l2))
lists = mergedLists
return lists[0]
"""
Refer Neetcode Video
Merging in Pairs
Updating Lists
"""