Leetcode Practise

Reverse Linked List

https://leetcode.com/problems/reverse-linked-list/

Solution

# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, val=0, next=None):
#         self.val = val
#         self.next = next
class Solution:
    def reverseList(self, head: Optional[ListNode]) -> Optional[ListNode]:
        if not head:
            return
        if head.next == None:
            return head

        prev = None
        curr = head
        after = curr.next

        while after:
            curr.next = prev
            prev = curr
            curr = after
            after = after.next

        curr.next = prev
        return curr

Middle of the Linked List

https://leetcode.com/problems/middle-of-the-linked-list/

Palindrome Linked List

https://leetcode.com/problems/palindrome-linked-list/

Reverse Linked List II

https://leetcode.com/problems/reverse-linked-list-ii/