19. Remove Nth Node From End of List

https://leetcode.com/problems/remove-nth-node-from-end-of-list/

JavaScript

/**
 * Definition for singly-linked list.
 * function ListNode(val) {
 *     this.val = val;
 *     this.next = null;
 * }
 */
/**
 * @param {ListNode} head
 * @param {number} n
 * @return {ListNode}
 */
var removeNthFromEnd = function(head, n) {
  var temp = new ListNode()
  temp.next = head

  var slow = temp
  var fast = temp

  for (let i = 0; i < n; i++) {
    fast = fast.next
  }

  while (fast.next) {
    slow = slow.next
    fast = fast.next
  }

  slow.next = slow.next.next
  return temp.next
}

Python

# Definition for singly-linked list.
# class ListNode(object):
#     def __init__(self, x):
#         self.val = x
#         self.next = None


class Solution(object):

    def removeNthFromEnd(self, head, n):
        """
        :type head: ListNode
        :type n: int
        :rtype: ListNode
        """
        temp, temp.next = ListNode(None), head
        slow = fast = temp

        for i in range(n):
            fast = fast.next

        while fast.next:
            slow, fast = slow.next, fast.next

        slow.next = slow.next.next
        return temp.next

Go

/**
 * Definition for singly-linked list.
 * type ListNode struct {
 *     Val int
 *     Next *ListNode
 * }
 */
func removeNthFromEnd(head *ListNode, n int) *ListNode {
    temp := &ListNode{
        Next: head,
    }
    fast := temp
    slow := temp
    for i := 0; i < n; i++ {
        fast = fast.Next
    }
    for fast.Next != nil {
        fast = fast.Next
        slow = slow.Next
    }
    slow.Next = slow.Next.Next
    return temp.Next
}