SDE - 1

You are given a reference/address of a node in a connected undirected graph containing N nodes and M edges. You are supposed to return a clone of the given graph which is nothing but a deep copy. Each node in the graph contains an integer “data” and an array/list of its neighbours.

The structure of the graphNode class is as follows:

class graphNode 
{  
    public:
        int data;
        vector<graphNode*> neighbours;
}

Note :

1. Nodes are numbered from 1 to N.

2. Your solution will run on multiple test cases. If you are using global variables make sure to clear them.

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?

What are types of keys explain them all

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.