What processes occur when a new element is added to a stack implemented via a linked list?

When adding a new element to a stack implemented via a linked list, the following occurs:

1. A new node (list element) is created, which stores the value to be added.
2. The pointer of the new node is set to the current top element of the stack (i.e., the head of the linked list).
3. The head of the linked list is updated to point to the new node — it becomes the new top element of the stack.

Thus, the push operation is performed in constant time O(1), as it does not require traversing the list.

Example in Kotlin:

class Node<T>(val value: T, var next: Node<T>? = null)

class Stack<T> {
    private var head: Node<T>? = null

    fun push(value: T) {
        val newNode = Node(value)
        newNode.next = head
        head = newNode
    }

    fun pop(): T? {
        val value = head?.value
        head = head?.next
        return value
    }
}