Remove nth node from end of list

Linked List Two Pointers

51.0% acceptance

Jan 12, 2026

21109

899

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

Solution

Rust

Time O(n)

Space O(1)

LeetCode

solution.rs

impl Solution {
  pub fn remove_nth_from_end(head: Option<Box<ListNode>>, n: i32) -> Option<Box<ListNode>> {
    let mut dummy = Box::new(ListNode { val: 0, next: head });
    let mut fast = &dummy.clone();
    
    // Move fast pointer n steps ahead
    for _ in 0..n {
      fast = fast.next.as_ref().unwrap();
    }
    
    // Move both pointers until fast reaches the end
    let mut slow = &mut dummy;
    while fast.next.is_some() {
      fast = fast.next.as_ref().unwrap();
      slow = slow.next.as_mut().unwrap();
    }
    
    // Remove the nth node from end
    let next = slow.next.as_mut().unwrap().next.take();
    slow.next = next;
    
    dummy.next
  }
}