I got a call from amazon for opening in SDE – I. It started with a online screening round and followed by one telephonic and then 3 face to face interview and again a telephonic interview.

**Online screening :**

There were 20 multiple choice questions from Computer science fundamentals (OS, DS, DBMS, Networks etc.) and basic input/output questions, some aptitude questions and 2 coding questions:-

1. Given an array find the minimum difference between any pair.

2. Write a function that returns true if a given undirected graph is tree and false otherwise. http://geeksquiz.com/check-given-graph-tree

**Telephonic Interview :**

Interview started with brief introduction about me and my projects, then started with coding questions.

1. Given two trees return yes if the order of leaves in tree are mirror image of each other.

2. Given an array of n numbers. another array with same elements but numbers are shuffled and one element is removed. Find the missing element.(without using any extra space and in O(n) ).

Then if both the array are sorted then how to find the missing element. (without extra space and in O(log n)).

Then they called me for onsite interview and 3 face to face interview were conducted there.

**Face-to-Face Interview 1 :**

He started with a brief introduction and asked me my about my projects in detail.

then moved to coding questions:-

1. Arrange Linked List elements in zig-zag pattern such that a < b > c < d > e ……

(without using extra space and Time complexity O(n)).

Don’t forget to handle edge cases.

(This is array implementation of same question).

2. Given a binary tree. return sum of all Left Leaf nodes.

Left leaves meaning leaf node which is left child of his parent.

**Face-to-face Interview 2 :**

1. Given two nodes of a binary tree,check they are cousins or not. (Both Iterative and recursive solution).

https://www.geeksforgeeks.org/check-two-nodes-cousins-binary-tree

2. Given an array with N elements (numbers from 0 to N-1). Find all duplicate elements.

I gave a solution with hashing, he asked me to do without extra space.

Then I gave solution with sorting the array, he asked me to do with only single traversal and without extra space.

**Face-to-face Interview 3 :**

Started with brief introduction and some questions from my projects and CS fundamentals (OS,Networks).

1.Given an input string and a dictionary of words, find out if the input string can be segmented into a space-separated sequence of dictionary words.

**Telephonic Interview :**

The interviewer asked me to introduce myself, and after that he asked some behavioural question like-

Have you got offer from any other company ?

Why are you intersted in joining AMAZON ?

1. Design a Elevator. How you store the input from users inside the elevator, outside the elevator. How the elevator will take decision whether to go up,down or stop.

2. There is an event in the auditorium and Given capacity of the auditorium (NxM). every group of person booked ticket and all the tickets are booked, Now you have to assign seat number to all of them such that minimum number of group split.