# Amazon Interview Experience for SDE-2

# 1st Round :

Q 1. Given an input string (`s`

) and a pattern (`p`

), implement wildcard pattern matching with support for `'?'`

and `'*'`

.

‘?’ Matches any single character.

‘*’ Matches any sequence of characters (including the empty sequence).

**Example :**

**Input:**

s = “adceb”

p = “*a*b”**Output:** true**Explanation:** The first ‘*’ matches the empty sequence, while the second ‘*’ matches the substring “dce”.

Q 2. https://www.geeksforgeeks.org/min-cost-path-dp-6/

Q3 . Given an array `nums`

of *n* integers, are there elements *a*, *b*, *c* in`nums`

such that *a* + *b* + *c* = 0? Find all unique triplets in the array which gives the sum of zero.

**Example:**

Given array nums = [-1, 0, 1, 2, -1, -4],

A solution set is:

[

[-1, 0, 1],

[-1, -1, 2]

]

# 2nd Round

Q 1 Given an array A of strings, find any smallest string that contains each string in `A`

as a substring.

We may assume that no string in `A`

is substring of another string in `A`

.

**Example 1:**

**Input:** [“alex”, “loves”, “leetcode”]**Output:** “alexlovesleetcode”**Explanation:** All permutations of “alex”, “loves”, “leetcode” would also be accepted.

Q 2 https://www.geeksforgeeks.org/minimum-time-required-so-that-all-oranges-become-rotten/

Q 3 https://www.geeksforgeeks.org/lowest-common-ancestor-in-a-binary-search-tree/

# Round 3

Q1 Given an unsorted array, find the maximum difference between the successive elements in its sorted form.**Input:** [3, 6, 9, 1]**Output:** 3**Explanation:** The sorted form of the array is [1, 3, 6, 9], either

(3, 6) or (6, 9) has the maximum difference 3.

Q 2

Input binary is given

Example :“010”

replace

0 with 01

1 with 10.

given k, m

k is iteration, m is index

tell what is present at m index

example k= 2, m=3

010

iteration 1–011001

iteration 2–011010010110

ans : 0 ( value at 3rd index, 2nd iteration)

Q 3 https://www.geeksforgeeks.org/egg-dropping-puzzle-dp-11/

# Round 4 (Design)

Design Amazon Locker

HLD, class diagram, Scaling, security issues. how will you handle security issues.

Also design amazon lockers reporting Manager tool for developers ( if developer wants to know any status of any locker… then a detail report should be provided for developer)

Detailed discussion went for around 1.5 hours.

Tip : Make your design Asynchronous

# Round 5 Hiring Manager

Q 1

Lot of Behavioural Questions

Biggest Achievement and failure

Conflict with Manager, how did you resolved

How can you improve your best work you have done till now

Q2

Design Snake & Ladder multiplayer game

HLD and LLD both were discussed in detail

How will you store your view on the server (Big discussion on it)

How will snake and ladders coordinates data will be stored on the server of current game session, if Snake and Ladder board is random for every game session (position of snakes and Ladders coordinate position should be random for every session of game)

# Round 6 (Bar Raiser)

Q 1 Lot of Behavioural Question

Q2 Design Inventory for 1000 employees in Amazon for any product of your choice(like laptops etc)

class level diagram, HLD

Main Emphasis was on Design patterns used in class diagram

Q3

Given a **non-empty** array of numbers, a0, a1, a2, …, an-1, where 0 ? ai < 231.

Find the maximum result of ai XOR aj, where 0 ? *i*, *j* < *n*.

O(N) complexity was expected**Example:**

**Input:** [3, 10, 5, 25, 2, 8]

**Output:** 28

**Explanation:** The maximum result is **5** ^ **25** = 28.

# Result : Hired !

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