Remove Nth Node From End of List

19. Remove Nth Node From End of List

Difficulty: Medium

Related Topics: Array, Linked List

Given the head of a linked list, remove the nth node from the end of the list and return its head.

Example 1:

Input: head = [1,2,3,4,5], n = 2 Output: [1,2,3,5]

Example 2:

Input: head = [1], n = 1 Output: []

Example 3:

Input: head = [1,2], n = 1 Output: [1]

Code:

# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, val=0, next=None):
#         self.val = val
#         self.next = next
class Solution:
    def removeNthFromEnd(self, head: Optional[ListNode], n: int) -> Optional[ListNode]:
        i, j = head, head
        for k in range(n):
            j = j.next
        if j == None: return head.next
        while j.next != None:
            i = i.next
            j = j.next
        i.next = i.next.next
        return head

Feedbacks:

Acutally, I am not quite understanding the logic of linked list. So, I got helped from solutions of other users. Need to work on linked list more than other algorithms.