C++ queue LINKED LIST implementation

1//PART A: Complete the code below (do not use any standard libraries). 3 //PART B: For each public method, provide a big-oh bound on the worst case 4 //run-time for that method in terms of the number of items 'n' contained in 5 //the data structure at the time of the method call. Justify your bound in each case 7class queueLL 9 private: //put what you need here.. 2 public: queueLL () //your code here queueLL () /your code here //add item to back of queue enqueue (int x) //your code here //remove and return first item from queue dequeue () //your code here