# Amazon Interview | Set 13

Last Updated : 13 Jun, 2019

Q2. Find immediate ancestor of a given Node
Q3. Clone the linked list having an extra random pointer in nodes which is pointing random node in the list.

Round 2 (F2F)
Q1 In a binary tree, a random pointer is given in each node. If this pointer pointing other than any successor of the node then set it as NULL. Otherwise let it remain untouched. Write code.

Q2. You will be given the number of pairs of parenthesis. Find out the total possible valid unique combinations and there should not be any duplicity. Write code

Round 3 (F2F)
Project and some questions related to it.
Q1 Given an in-order traversal of a special binary tree having property that the node is always greater than its left and right child. Construct the tree and write code.
Q2 Find top 10 trending words inserted by users in sites like twitter. Only algorithm.

Round 4 (Telephonic)
Q1. Remove duplicated from a string in O(n) without using hash.

Q2. Find the first occurrence of 1 in a sorted infinite binary tree.

Round 5 (F2F)
Amazon has many visitors to its site. And it tracks what pages the customers visited, etc and other stuff.
Make an efficient data structure for storing 3 days of information of all those customers who have visited site exactly two different days and searched more than 3 unique pages of the site in those 2 days.

So whoever visited site exactly two days out of these three days and visited more then 3 unique pages should be in the contact list.

After final round got a regret mail after 3 days that I was Not selected.