SDE - 2

You have been given a number of stairs. Initially, you are at the 0th stair, and you need to reach the Nth stair.

Each time, you can climb either one step or two steps.

You are supposed to return the number of distinct ways you can climb from the 0th step to the Nth step.

Note:

Note: Since the number of ways can be very large, return the answer modulo 1000000007.

Example :

N=3

We can climb one step at a time i.e. {(0, 1) ,(1, 2),(2,3)} or we can climb the first two-step and then one step i.e. {(0,2),(1, 3)} or we can climb first one step and then two step i.e. {(0,1), (1,3)}.

You are given a linked list containing 'n' nodes, where every node in the linked list contains two pointers:

(1) ‘next’ which points to the next node in the list

(2) ‘random’ which points to a random node in the list or 'null'.

Your task is to create a 'deep copy' of the given linked list and return its head.

Note:

A 'deep copy' of a linked list means we do not copy the references of the nodes of the original linked list, rather for each node in the original linked list, a new node is created.