Software Developer

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 are given an arbitrary binary tree consisting of 'N' nodes numbered from 1 to 'N'. Your task is to print all the root to leaf paths of the binary tree.

A leaf of a binary tree is the node which does not have a left child and a right child.

For Example :

Given a binary tree :

All the root to leaf paths are :
1 2 4
1 2 5 
1 3

Note :

1. Two nodes may have the same value associated with it.
2. The root node will be fixed and will be provided in the function.
3. Note that the nodes in a path will appear in a fixed order. For example, 1 2 3 is not the same as 2 1 3.
4. Each path should be returned as a string consisting of nodes in order and separated by a space.
5. The path length may be as small as ‘1’.

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.

You are given an infinite supply of coins of each of denominations D = {D0, D1, D2, D3, ...... Dn-1}. You need to figure out the total number of ways W, in which you can make a change for value V using coins of denominations from D. Print 0, if a change isn't possible.