Sample Linked List.swift

Sample Linked List.swift

import UIKit

class Node {
    let value: Int
    var next: Node?
    
    init(_ value:Int, _ next: Node?) {
        self.value = value
        self.next = next
    }
}

class LinkedList {
    
    var head: Node?
    
    func displayListItems() {
        print("Here is whats inside of your list:")
        
        var current = head
        while current != nil {
            print(current?.value ?? "")
            current = current?.next
        }
        
    }
    
    func insert(_ value: Int) {
        
        // empty list
        if head == nil {
            head = Node(value, nil)
            return
        }
        
        var current = head
        
        while current?.next != nil {
            current = current?.next
        }
        
        current?.next = Node(value, nil)
    }
    
    func delete(_ value: Int) {
        if head?.value == value {
            head = head?.next
        }
        
        var prev: Node?
        var current = head
        
        while current != nil && current?.value != value {
            prev = current
            current = current?.next
        }
        
        prev?.next = current?.next
        
    }
    
    func setupDummyNodes() {
        let three = Node(3, nil)
        let two = Node(2, three)
        head = Node(1, two)
    }
    
}

let sampleList = LinkedList()
//sampleList.setupDummyNodes()
sampleList.insert(1)
sampleList.insert(2)
sampleList.insert(3)

sampleList.delete(3)

sampleList.displayListItems()