LeetCode Entry

2095. Delete the Middle Node of a Linked List

15.06.2026 medium 2026 kotlin rust

Remove the middle of Linked LIst

2095. Delete the Middle Node of a Linked List medium substack youtube

https://dmitrysamoylenko.com/leetcode/

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Problem TLDR

Remove the middle of Linked LIst

Intuition

• fast & slow pointer
• count, then walk again

Approach

• Rust: fast & slow can be done with unsafe + raw pointers

Complexity

• Time complexity: \(O(n)\)

• Space complexity: \(O(1)\)

Code

    fun deleteMiddle(h: ListNode?) = run {
        val d = ListNode(0).apply{next = h}
        var s: ListNode? = d; var f = h
        while(f?.next!=null){s = s?.next;f=f?.next?.next}
        s?.next = s?.next?.next; d.next
    }

    pub fn delete_middle(mut h: Option<Box<ListNode>>) -> Option<Box<ListNode>> {
        let mut cnt = 0; let mut s = &h;
        while let Some(n) = &s { s = &n.next; cnt += 1 }
        if cnt <= 1 { return None } let mut s = &mut h;
        for i in 0..cnt/2-1 { s = &mut s.as_mut().unwrap().next  }
        let mid = s.as_mut().unwrap().next.take();
        s.as_mut().unwrap().next = mid.and_then(|mut n| n.next.take());
        h
    }