operations for ListNode like classes

nodes.kt

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


fun <T> buildNodeList(vararg items: T): Node<T>? {
    if (items.isEmpty())
        return null

    val head = Node(items.first())

    if (items.size == 1) return head

    var previous = head
    for (i in 1 until items.size) {
        val currentNode = Node(items[i])
        previous.next = currentNode
        previous = currentNode
    }
    return head
}

fun <T> Node<T>.forEach(block: (Node<T>) -> Unit) {
    var current: Node<T>? = this
    while (current != null) {
        block(current)
        current = current.next
    }
}