enqueue( peek( dequeue( standard queue queue is implicitly like that described prior to this section in dsa we don' provide standard queue because queues are so popular and such core data structure that you will find pretty much every mainstream library provides queue data structure that you can use with your language of choice in this section we will discuss how you canif requiredimplement an efficient queue data structure the main property of queue is that we have access to the item at the front of the queue the queue data structure can be efficiently implemented using singly linked list (defined in ss singly linked list provides ( insertion and deletion run time complexities the reason we have an ( run time complexity for deletion is because we only ever remove items from the front of queues (with the dequeue operationsince we always have pointer to the item at the head of singly linked listremoval is simply case of returning the value of the old head nodeand then modifying the head pointer to be the next node of the old head node the run time complexity for searching queue remains the same as that of singly linked listo( priority queue unlike standard queue where items are ordered in terms of who arrived firsta priority queue determines the order of its items by using form of custom comparer to see which item has the highest priority other than the items in priority queue being ordered by priority it remains the same as normal queueyou can only access the item at the front of the queue sensible implementation of priority queue is to use heap data structure (defined in ss using heap we can look at the first item in the queue by simply returning the item at index within the heap array heap provides us with the ability to construct priority queue where the items with the highest priority are either those with the smallest valueor those with the largest double ended queue unlike the queues we have talked about previously in this double ended queue allows you to access the items at both the frontand back of the queue double ended queue is commonly known as deque which is the name we will here on in refer to it as deque applies no prioritization strategy to its items like priority queue doesitems are added in order to either the front of back of the deque the former properties of the deque are denoted by the programmer utilising the data structures exposed interface