Merge k Sorted Lists - LeetCode 23 - Python

[@deepakjyoti8355]

Your videos are informative, entertaining and educational.

[@Drdoggo24]

Great consistency, motivated me to start again 😅 high time I do lol
Also I love the way you’re using collections and heaps. Although I gain an overall intuition before I watch the explanation, it’s hard to code those small things that don’t need coding from scratch. So thanks for keeping it simple !

[@vinuu.k]

Why do you use python3 rather than python...?!

[@jst8922]

LC linked list hard question, not actually my favorite topic :P
I see you used heaps (min), not beginner friendly stuff and complicated solution.
imho: NC solution is easier to understand:
# 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
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(self.mergeList(l1, l2))
lists = mergedLists
return lists[0]
def mergeList(self, l1, l2):
dummy = ListNode()
tail = dummy
while l1 and l2:
if l1.val < l2.val:
tail.next = l1
l1 = l1.next
else:
tail.next = l2
l2 = l2.next
tail = tail.next
if l1:
tail.next = l1
if l2:
tail.next = l2
return dummy.next