Software Engineer

Ninja is feeling very bored and wants to try something new. So, he decides to find the reverse of a given number. But he cannot do it on his own and needs your help.

Note:

If a number has trailing zeros, then its reverse will not include them. For e.g., the reverse of 10400 will be 401 instead of 00401.

Given a singly linked list of integers. Your task is to return the head of the reversed linked list.

For example:

The given linked list is 1 -> 2 -> 3 -> 4-> NULL. Then the reverse linked list is 4 -> 3 -> 2 -> 1 -> NULL and the head of the reversed linked list will be 4.

Follow Up :

Can you solve this problem in O(N) time and O(1) space complexity?

You will be given ‘Q’ queries. You need to implement a queue using two stacks according to those queries. Each query will belong to one of these three types:

1 ‘X’: Enqueue element ‘X’  into the end of the nth queue. Returns true after the element is enqueued.

2: Dequeue the element at the front of the nth queue. Returns -1 if the queue is empty, otherwise, returns the dequeued element.

Note:

Enqueue means adding an element to the end of the queue, while Dequeue means removing the element from the front of the queue.