In a queue implemented using two stacks, what is the time complexity of the dequ
Practice Questions
Q1
In a queue implemented using two stacks, what is the time complexity of the dequeue operation in the worst case?
O(1)
O(n)
O(log n)
O(n log n)
Questions & Step-by-Step Solutions
In a queue implemented using two stacks, what is the time complexity of the dequeue operation in the worst case?
Step 1: Understand what a queue is. A queue is a data structure that follows the First In First Out (FIFO) principle.
Step 2: Know that we can implement a queue using two stacks. A stack is a data structure that follows the Last In First Out (LIFO) principle.
Step 3: Identify the two stacks: let's call them Stack A and Stack B.
Step 4: When we want to dequeue (remove an element from the front of the queue), we need to check if Stack B is empty.
Step 5: If Stack B is empty, we need to transfer all elements from Stack A to Stack B. This means popping each element from Stack A and pushing it onto Stack B.
Step 6: The transfer of elements from Stack A to Stack B takes time proportional to the number of elements in Stack A, which is O(n) in the worst case.
Step 7: If Stack B is not empty, we can simply pop the top element from Stack B, which takes O(1) time.
Step 8: Therefore, in the worst case, the dequeue operation requires transferring all elements from Stack A to Stack B, resulting in O(n) time complexity.
