Linked List Deletion

Visualization

Watch how elements are removed from a linked list:

Types of Deletion

1. Delete from Head

• Time Complexity: O(1)
• Most efficient deletion operation

public void deleteHead() {
    if (head != null) {
        head = head.next;
    }
}

2. Delete from Tail

• Time Complexity: O(n)
• Requires traversal to second-last node

public void deleteTail() {
    if (head == null || head.next == null) {
        head = null;
        return;
    }
    
    ListNode current = head;
    while (current.next.next != null) {
        current = current.next;
    }
    current.next = null;
}

3. Delete by Value

• Time Complexity: O(n)
• Requires traversal to find value

public void deleteValue(int val) {
    if (head == null) return;
    
    if (head.val == val) {
        head = head.next;
        return;
    }
    
    ListNode current = head;
    while (current.next != null && current.next.val != val) {
        current = current.next;
    }
    
    if (current.next != null) {
        current.next = current.next.next;
    }
}

Common Deletion Patterns

1. Using dummy head node
2. Two-pointer technique
3. Handle edge cases (empty list, single node)
4. Recursive deletion