4. Two Stacks can make a Queue A well implemented stack has two operations that it can support in O(1) time: Push and Pop. It turns out that it is possible to implement an efficient queue using only two stacks. A queue has two supported operations: Enqueue: where a value is pushed into the rear of the queue. Dequeue: where a value is popped from the front of the queue. (a) [2pts] Describe how a queue can be implemented using two stacks. (Hint: a more standard queue implementation typically tracks two values: front and rear. You have two stacks to use. (b) [2pts| Using the accounting method from class, prove that your stack-based queue has the property that any sequence of n operations (selected from Enqueue and Dequeue) takes a total of O(n) time resulting in amortized O(1) time for each of these operations! 4. Two Stacks can make a Queue A well implemented stack has two operations that it can support in O(1) time: Push and Pop. It turns out that it is possible to implement an efficient queue using only two stacks. A queue has two supported operations: Enqueue: where a value is pushed into the rear of the queue. Dequeue: where a value is popped from the front of the queue. (a) [2pts] Describe how a queue can be implemented using two stacks. (Hint: a more standard queue implementation typically tracks two values: front and rear. You have two stacks to use. (b) [2pts| Using the accounting method from class, prove that your stack-based queue has the property that any sequence of n operations (selected from Enqueue and Dequeue) takes a total of O(n) time resulting in amortized O(1) time for each of these operations