C # linkedlist<t> doubly linked list

InterfaceImylist<t>{    //O (1)//ADD an item at the beginning of the list.    voidAddFirst (T item); //O (1)//ADD an item at the end of the list.    voidaddlast (T itme); //O (1)//Remove the item from the list. If The list contains multiple//copies/references of the item, remove one of them.    voidRemove (T item); //O (1)//Reverse the list.    voidReverse ();}classMylist<t>: imylist<t>, ienumerable{Private BOOL_isreverse =false;/PrivateLinkedlist<t> _list =NewLinkedlist<t> ();//doubly linked list <br>    PrivateDictionary<t, list<linkedlistnode<t>>> _dict =NewDictionary<t, list<linkedlistnode<t>>> ();//used to temporarily store node      Public voidAddFirst (T item) {LinkedListNode<T> node = _isreverse?_list. AddLast (item): _list.        AddFirst (item);    Adddict (item, node); }     Private voidAdddict (T item, linkedlistnode<t>node) {List<LinkedListNode<T>> samelist =NULL; if(!_dict. TryGetValue (Item, outsamelist)) {Samelist=NewList<linkedlistnode<t>>(); } samelist.        ADD (node); _dict[item]=samelist; }      Public voidaddlast (T item) {LinkedListNode<T> node = _isreverse?_list. AddFirst (item): _list.        AddLast (item);    Adddict (item, node); }      Public voidRemove (T item) {List<LinkedListNode<T>> samelist =NULL; if(_dict. TryGetValue (Item, outsamelist)) {            if(Samelist.count >0) {_list. Remove (samelist[0]); Samelist.removeat (0); _dict.            Remove (item); }        }     }      Public voidReverse () {_isreverse= !_isreverse;; }     /// <summary>    ///implementation of Iterators/// </summary>    /// <returns></returns>     PublicIenumerator<t>GetEnumerator () {LinkedListNode<T>node; if(!_isreverse) Node=_list.        First; Elsenode=_list.         Last;  while(true)        {            if(node = =NULL)                yield  Break; yield returnnode.             Value; if(!_isreverse) Node=node.            Next; Elsenode=node.        Previous; }    }     /// <summary>    ///implementing iterations because he doesn't have a generic type./// </summary>    /// <returns></returns>IEnumerator Ienumerable.getenumerator () {returnGetEnumerator (); }}

C # linkedlist<t> doubly linked list