Delete the middle node of a linked list

Linked List Two Pointers

59.5% acceptance

Feb 25, 2026

4904

105

You are given the head of a linked list. Delete the middle node, and return the head of the modified linked list. The middle node of a linked list of size n is the floor(n/2)th node from the start using 0-based indexing. For n = 1, 2, 3, 4, and 5, the middle nodes are 0, 1, 1, 2, and 2, respectively.

Solution

Rust

Time O(n)

Space O(n)

LeetCode

solution.rs

impl Solution {
  pub fn delete_middle(head: Option<Box<ListNode>>) -> Option<Box<ListNode>> {
    // Collect values, remove middle, rebuild
    let mut vals = Vec::new();
    let mut cur = &head;
    while let Some(node) = cur {
      vals.push(node.val);
      cur = &node.next;
    }
    let n = vals.len();
    if n == 0 {
      return None;
    }
    let mid = n / 2;
    vals.remove(mid);

    let mut dummy = Box::new(ListNode::new(0));
    let mut cur = &mut dummy;
    for &v in &vals {
      cur.next = Some(Box::new(ListNode::new(v)));
      cur = cur.next.as_mut().unwrap();
    }
    dummy.next
  }
}