SwiftでLinkedList ref: http://qiita.com/toshi0383/items/c10d2f739d4fa8f9f7a6

file0.swift

class LLNode<T> {
    var key: T? = nil
    var next: LLNode? = nil
    var prev: LLNode? = nil
    init() {
    }
    init(PREV prev:LLNode!, KEY key:T!, NEXT next:LLNode!) {
        self.prev = prev
        self.key = key
        self.next = next
    }
}

class LinkedList<T: Equatable> {
    private var head: LLNode<T> = LLNode<T>()
    private var tail: LLNode<T> = LLNode<T>()

    func appendKey(key: T) {
        var l = tail
        var newNode = LLNode<T>(PREV:l, KEY:key, NEXT:nil)
        tail = newNode
        if (l.key == nil) {
            head = newNode
        } else {
            l.next = newNode
        }
    }
    func removeKey(key: T) {
        var node: LLNode? = head
        while (node?.key != nil) {
            if (node?.key! == key) {
                unlink(node!)
                break
            }
            node = node?.next
        }
    }
    func unlink(element: LLNode<T>) {
        let __prev = element.prev
        let __next = element.next
        if (__prev?.key == nil) {
            if let n = __next {
                head = n
            }
        } else {
            __prev?.next = __next
            element.prev = nil
        }
        if (__next?.key == nil) {
            tail = __prev!
        } else {
            __next?.prev = __prev
            element.next = nil
        }
        element.key = nil
    }

    func print() {
        var current: LLNode? = head
        var str: String = String()
        while (current != nil) {
            if let key = current?.key {
                println(key)
            }
            current = current?.next
        }
    }
}

var list = LinkedList<String>()
list.appendKey("a")
list.appendKey("b")
list.appendKey("c")
list.print()
list.removeKey("a")
list.print()
list.removeKey("c")
list.print()