Amazon Lead Operator Interview Questions and Answers

Round duration - 90 minutes
Round difficulty - Hard

This was an online coding round where we were supposed to solve 2 questions under 90 minutes . Both the questions in my set were related to Graphs and were quite tricky and heavy to implement.

Q1. 
Path Counting in Directed Graph
Given a directed graph with a specified number of vertices V and edges E, your task is to calculate the total number of distinct paths from a given source node S to all ot...read more
Ans. 
Calculate the total number of distinct paths from a given source node to all other nodes in a directed graph.
• Use dynamic programming to keep track of the number of paths from the source node to each node in the graph.

• Consider using modular arithmetic to handle large numbers and prevent overflow.

• Start by initializing the number of paths from the source node to itself as 1.

• Iterate through the edges of the graph and updat...read more
Answered by AI
View 2 more answers
Q2. 
Course Schedule II Problem Statement
You are provided with a number of courses 'N', some of which have prerequisites. There is a matrix named 'PREREQUISITES' of size 'M' x 2. This matrix indicates that fo...read more
Ans. 
Given courses with prerequisites, determine a valid order to complete all courses.
• Use topological sorting to find a valid order of courses.

• Create a graph with courses as nodes and prerequisites as edges.

• Start with courses that have no prerequisites and remove them from the graph.

• Continue this process until all courses are taken or there are no valid courses left.

• If there is a cycle in the graph, it is impossible to com
Answered by AI
Add your answer

Round duration - 60 Minutes
Round difficulty - Medium

This was a Data Structures and Algorithms round with some standard questions . I was expected to come up with an
efficient approach and code it as well .

Q1. 
Merge Intervals Problem Statement
You are provided with 'N' intervals, each containing two integers denoting the start time and end time of the interval.
Your task is to merge all overlapping intervals a...read more
Ans. 
Merge overlapping intervals and return sorted list of merged intervals.
• Sort the intervals based on start times.

• Iterate through intervals and merge overlapping intervals.

• Return the merged intervals in sorted order.
Answered by AI
Add your answer
Q2. 
Longest Route Problem Statement
Given a 2-dimensional binary matrix called Mat of size N x M that consists solely of 0s and 1s, find the length of the longest path from a specified source cell to a destina...read more
Ans. 
Find the length of the longest path from a source cell to a destination cell in a binary matrix.
• Use depth-first search (DFS) to explore all possible paths from source to destination.

• Keep track of visited cells to avoid revisiting them.

• Return the length of the longest path found, or -1 if no path exists.
Answered by AI
Add your answer

Round duration - 50 Minutes
Round difficulty - Medium

This was also a DSA round where I was asked to code only one of the questions but I eventually ended up coding both
as I had some spare time and explained my approches very smoothly to the interviewer . This round went preety well .

Q1. 
Longest Increasing Subsequence Problem Statement
Given an array of integers with 'N' elements, determine the length of the longest subsequence where each element is greater than the previous element. This...read more
Ans. 
Find the length of the longest strictly increasing subsequence in an array of integers.
• Use dynamic programming to solve this problem efficiently.

• Initialize an array to store the length of the longest increasing subsequence ending at each index.

• Iterate through the array and update the length of the longest increasing subsequence for each element.

• Return the maximum value in the array as the result.
Answered by AI
Add your answer
Q2. 
Search In Rotated Sorted Array Problem Statement
Given a rotated sorted array ARR of size 'N' and an integer 'K', determine the index at which 'K' is present in the array.
Note:
1. If 'K' is not present...read more
Ans. 
Given a rotated sorted array, find the index of a given integer 'K'.
• Use binary search to find the pivot point where the array is rotated.

• Then perform binary search on the appropriate half of the array to find 'K'.

• Handle cases where 'K' is not present in the array by returning -1.
Answered by AI
Add your answer

Round duration - 50 Minutes
Round difficulty - Medium

This was also a DSA round with 2 questions of Medium to Hard difficulty . I was expected to follow some clean code and OOPS principles to write the code in this round .

Q1. 
Rank from Stream Problem Statement
Given an array of integers ARR and an integer K, determine the rank of the element ARR[K].
Explanation:
The rank of any element in ARR is defined as the number of elem...read more
Ans. 
Given an array and an index, find the number of elements smaller than the element at that index appearing before it in the array.
• Iterate through the array up to index K and count the number of elements smaller than ARR[K].

• Return the count as the rank of ARR[K].

• Handle edge cases like empty array or invalid index K.
Answered by AI
Add your answer
Q2. 
LRU Cache Design Question
Design a data structure for a Least Recently Used (LRU) cache that supports the following operations:
1. get(key) - Return the value of the key if it exists in the cache; otherw...read more
Ans. 
Design a Least Recently Used (LRU) cache data structure that supports get and put operations with capacity constraint.
• Implement a doubly linked list to maintain the order of recently used keys.

• Use a hashmap to store key-value pairs for quick access.

• Update the order of keys in the linked list on get and put operations.

• Evict the least recently used key when the cache reaches its capacity.
Answered by AI
Add your answer

It was a medium-level DSA round

This was also a DSA round

This again a DSA round

Q1. Can't disclose the question because of NDA signed but it was a design round
Add your answer

Q1. This was a project discussion round
Add your answer

Q1. They will ask about your profile and past experience.
Add your answer

Q1. A peer level colleague will ask some basic knowledge check questions
Add your answer

This is literally a live coding test. For analytics expect SQL, python, R.

Q1. Interviewed by a manager of another team
Add your answer

Q1. Interviewed by dotted line reporting manager
Add your answer

Q1. Cross functional interview
Add your answer

Q1. Core Values Interview
Add your answer

Implement an iterator to flatten 2D vector

Q1. Find shortest path to get all keys
Ans. 
Use Dijkstra's algorithm to find the shortest path to get all keys
• Implement Dijkstra's algorithm to find the shortest path in a graph

• Consider the keys as nodes in the graph and the paths between keys as edges

• Keep track of the keys collected and update the shortest path accordingly
Answered by AI
Add your answer

Q1. Tell me about a time when you hosted someone
Add your answer
Q2. What is trauma according to you
Ans. 
Trauma is a psychological response to a distressing event that overwhelms an individual's ability to cope.
• Trauma can result from experiences such as accidents, abuse, natural disasters, or violence

• It can lead to symptoms like anxiety, depression, flashbacks, and difficulty sleeping

• Treatment for trauma often involves therapy, medication, and support from loved ones
Answered by AI
Add your answer
Q3. Explain the most difficult situation you have handled
Add your answer
Q4. Tell me about a time you mand how you made a mistake and your learning
Ans. 
I once made a mistake by misinterpreting a client's request, but I learned the importance of active listening and clarifying details.
• Misinterpreted a client's request due to lack of clarity

• Resulted in delivering the wrong product to the client

• Learned the importance of active listening and clarifying details before proceeding

• Implemented a process of repeating back instructions to ensure understanding
Answered by AI
Add your answer

Q1. What was the time you hosted someone
Add your answer
Q2. Tell me your biggest mistake
Ans. 
My biggest mistake was not delegating tasks effectively, leading to burnout and decreased team morale.
• Failed to prioritize tasks and delegate effectively

• Took on too much responsibility without seeking help

• Resulted in burnout and decreased team morale
Answered by AI
Add your answer