LeetCode 19 - Remove Nth Node From End of List Problem

Problem Statement

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

Example:

Given linked list: 1->2->3->4->5, and n = 2.

After removing the second node from the end, the linked list becomes 1->2->3->5.

Note:

Given n will always be valid.

Follow up:

Could you do this in one pass?

Solution:

# Definition for singly-linked list. # class ListNode: # def __init__(self, x): # self.val = x # self.next = None class Solution: def removeNthFromEnd(self, head: ListNode, n: int) -> ListNode: dummy_head = ListNode(0) dummy_head.next = head slow = dummy_head fast = dummy_head for _ in range(n+1): fast = fast.next while fast!=None: slow = slow.next fast = fast.next slow.next = slow.next.next return dummy_head.next