Remove Nth Node From End of List

LeetCode Q 19 - Remove Nth Node From End of List

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

Code:

public ListNode removeNthFromEnd(ListNode head, int n) {
	
	ListNode dummy = new ListNode(-1);
	dummy.next = head;

	ListNode slow = dummy, fast = dummy;

	for (int i = 0; i < n; i++) 
		fast = fast.next;

	while (fast.next != null) {
		slow = slow.next; fast = fast.next;    
	}

	low.next = slow.next.next;

	return dummy.next;
}