Uber SDE-2 Interview Questions, Process, and Tips

Round duration - 90 minutes
Round difficulty - Medium

Q1. 
Number of Islands Problem Statement
You are provided with a 2D array or list containing 'N' rows and 'M' columns, filled with 1s and 0s. Here, 1 indicates land, and 0 indicates water.
Your task is to ide...read more
Ans. 
Count the number of islands in a 2D matrix filled with 1s and 0s.
• Iterate through the matrix and perform depth-first search (DFS) to find connected islands.

• Use a visited array to keep track of visited cells to avoid redundant calculations.

• Increment the island count whenever a new island is encountered.

• Consider all eight directions (horizontal, vertical, and diagonal) while exploring the island.

• Handle edge cases like out
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Q2. 
Add First and Second Half Problem Statement
You are provided with a Singly Linked List having 'N' nodes, where each node contains a single digit.
Your task is to return a node 'X', which serves as the he...read more
Ans. 
Return a node representing the head of a new Linked List with the sum of the 1st and 2nd half of the given Linked List.
• Split the Linked List into two halves

• Reverse the 2nd half of the Linked List

• Add the corresponding digits from both halves while considering carry

• Create a new Linked List with the sum digits
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Round duration - 60 minutes
Round difficulty - Medium

Q1. 
Next Greater Element Problem Statement
You are given an array arr of length N. For each element in the array, find the next greater element (NGE) that appears to the right. If there is no such greater ele...read more
Ans. 
The task is to find the next greater element for each element in an array to its right, if no greater element exists, return -1.
• Use a stack to keep track of elements for which the next greater element is not found yet.

• Iterate through the array from right to left, popping elements from the stack until a greater element is found.

• Store the next greater element for each element in a separate array.

• If the stack is empty aft...read more
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Round duration - 60 Minutes
Round difficulty - Hard

Q1. 
Word Break Problem Statement
You are given a non-empty string without spaces, referred to as 'sentence', and a list of non-empty strings representing a dictionary. Your task is to construct and return all...read more
Ans. 
Given a sentence and a dictionary, construct and return all possible sentences by inserting spaces to form words from the dictionary.
• Use backtracking to generate all possible combinations of words from the dictionary to form sentences.

• Check if a substring of the sentence matches any word in the dictionary, if so, recursively call the function with the remaining substring.

• Continue this process until the entire sentence ...read more
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Q2. 
Valid Parenthesis Problem Statement
Given a string str composed solely of the characters "{", "}", "(", ")", "[", and "]", determine whether the parentheses are balanced.
Input:
The first line contains ...read more
Ans. 
Check if given string of parentheses is balanced or not.
• Use a stack to keep track of opening parentheses and pop when a closing parenthesis is encountered.

• If stack is empty at the end and all parentheses are matched, the string is balanced.

• If stack is not empty at the end or mismatched parentheses are encountered, the string is not balanced.
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Round duration - 60 minutes
Round difficulty - Easy

Q1. Design a local transport system similar to BMTC.
Ans. 
Design a local transport system similar to BMTC
• Introduce a fleet of buses covering various routes within the city

• Implement a smart card system for easy payment and tracking

• Include different types of buses like regular, AC, and Volvo for passenger comfort

• Have designated bus stops with real-time information on bus arrivals

• Offer discounted fares for students and senior citizens
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Round duration - 60 minutes
Round difficulty - Easy

2 coding questions

Q1. Ds algo round 2 medium questions
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Round duration - 1 hour
Round difficulty - Medium

This was coding round and was conducted on Google meet with code link shared. Their were 2 interviewers that gave questions and later ran code on sample test cases.

Q1. 
Print Permutations - String Problem Statement
Given an input string 'S', you are tasked with finding and returning all possible permutations of the input string.
Input:
The first and only line of input ...read more
Ans. 
Return all possible permutations of a given input string.
• Use recursion to generate all possible permutations of the input string.

• Swap characters at different positions to generate permutations.

• Handle duplicate characters by skipping swapping if the characters are the same.
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Q2. 
Find the Kth Row of Pascal's Triangle Problem Statement
Given a non-negative integer 'K', determine the Kth row of Pascal’s Triangle.
Example:
Input:
K = 2
Output:
1 1
Input:
K = 4
Output:
1 4 6 ...read more
Ans. 
The task is to find the Kth row of Pascal's Triangle given a non-negative integer K.
• Create an array to store the elements of the Kth row of Pascal's Triangle.

• Use the formula C(n, k) = C(n-1, k-1) + C(n-1, k) to calculate the elements.

• Return the array as the output.
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Round duration - 2 hours
Round difficulty - Medium

This was a Machine Coding Round/LLD round followed by HLD round which was taken by Video Conferencing and Screen Sharing.

Round duration - 75 minutes
Round difficulty - Medium

This was the last round. This was HM round followed by the HR round.

Round duration - 60 minutes
Round difficulty - Medium

It was a problem solving round where a hackerrank link was given containing 2 questions.
You have to solve them within 90 minutes.
I was asked to solve it within a week.

Q1. 
Find Distinct Palindromic Substrings
Given a string 'S', identify and print all distinct palindromic substrings within it. A palindrome reads the same forwards and backwards. For example, 'bccb' is a pali...read more
Ans. 
Given a string, find and print all distinct palindromic substrings within it.
• Iterate through all possible substrings of the input string

• Check if each substring is a palindrome

• Store distinct palindromic substrings in a set and then sort them before printing
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Round duration - 60 minutes
Round difficulty - Easy

2 questions was asked by the interviewer. You have to clearly explain your approach and write a working solution. He even asked me to run on some additional test cases

Q1. 
Job Sequencing Problem Statement
You are provided with a N x 2 2-D array called Jobs consisting of N jobs. In this array, Jobs[i][0] represents the deadline of the i-th job, while Jobs[i][1] indicates the...read more
Ans. 
Maximize profit by scheduling jobs within their deadlines.
• Sort the jobs based on their profits in descending order.

• Iterate through the sorted jobs and schedule them based on their deadlines.

• Keep track of the maximum profit achievable by scheduling jobs within their deadlines.
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Q2. 
Partition Equal Subset Sum Problem
Given an array ARR consisting of 'N' positive integers, determine if it is possible to partition the array into two subsets such that the sum of the elements in both sub...read more
Ans. 
The problem is to determine if it is possible to partition an array into two subsets with equal sum.
• Use dynamic programming to solve this problem efficiently.

• Create a 2D array to store the subset sum possibilities.

• Check if the total sum of the array is even before attempting to partition.

• Iterate through the array and update the subset sum array accordingly.

• Return true if the subset sum array contains a sum equal to hal
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Round duration - 60 minutes
Round difficulty - Easy

I was asked 1 system design question. The question was to design an online multiplayer game which can be scaled for more than 10 million users. 
The interviewer helped me to collect requirement and also helped me in choosing different low latency protocol to communicate between client and server.

Round duration - 60 minutes
Round difficulty - Medium

The interviewer asked few sql based questions and asked me to write the solution.
He also gave 1 problem solving question.

Q1. Can you explain the different types of joins in SQL and how to calculate the average of all values from a given table?
Ans. 
Different types of joins in SQL and calculating average of values from a table.
• Types of joins: INNER JOIN, LEFT JOIN, RIGHT JOIN, FULL JOIN

• To calculate average: Use AVG() function in SQL

• Example: SELECT AVG(column_name) FROM table_name
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Round duration - 60 Minutes
Round difficulty - Medium

Anytime

Q1. 
Problem: Sort an Array of 0s, 1s, and 2s
Given an array/list ARR consisting of integers where each element is either 0, 1, or 2, your task is to sort this array in increasing order.
Input:
The input sta...read more
Ans. 
The task is to sort an array of 0s, 1s, and 2s in increasing order.
• Use a three-pointer approach to partition the array into three sections: 0s, 1s, and 2s.

• Initialize three pointers: low, mid, and high. low points to the start of the array, mid points to the current element being processed, and high points to the end of the array.

• While mid <= high, if ARR[mid] is 0, swap ARR[low] and ARR[mid], increment low and mid. If
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Q2. 
Connect Ropes with Minimum Cost
Given 'N' ropes, each having different lengths, your task is to connect these ropes into one single rope. The cost to connect two particular ropes is equal to the sum of th...read more
Ans. 
The task is to connect N ropes into one rope with minimum cost.
• Sort the array of rope lengths in ascending order.

• Initialize a variable to keep track of the total cost.

• While there are more than one rope, take the two shortest ropes and connect them.

• Add the cost of connecting the two ropes to the total cost.

• Replace the two shortest ropes with the connected rope.

• Repeat the above steps until only one rope remains.

• Return th
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Round duration - 60 Minutes
Round difficulty - Medium

Q1. 
Maximum Subarray Sum Problem Statement
Given an array ARR consisting of N integers, your goal is to determine the maximum possible sum of a non-empty contiguous subarray within this array.
Example of Sub...read more
Ans. 
The task is to find the maximum possible sum of a non-empty subarray of an array.
• Iterate through the array and keep track of the maximum sum encountered so far

• If the current element is greater than the sum so far, start a new subarray

• If the current element plus the sum so far is greater than the maximum sum, update the maximum sum

• Return the maximum sum
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Q2. 
Diameter of a Binary Tree Problem Statement
Given a binary tree, return the length of its diameter. The diameter of a binary tree is defined as the length of the longest path between any two nodes in the ...read more
Ans. 
The diameter of a binary tree is the length of the longest path between any two end nodes in the tree.
• The diameter of a binary tree can be calculated by finding the maximum of the following three values: 1) the diameter of the left subtree, 2) the diameter of the right subtree, and 3) the longest path that passes through the root node.

• To find the diameter of a binary tree, we can use a recursive approach where we calcu...read more
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Round duration - 60 Minutes
Round difficulty - Medium

This round was more aroung sytem design and my past work experience.

Q1. Can you describe the system design for a platform like BookMyShow and the questions that were raised during the discussion?
Ans. 
Design a bookmyshow system
• Design a system to book and manage movie tickets

• Consider features like seat selection, payment, and ticket cancellation

• Include user authentication and authorization

• Implement a database to store movie and theater information

• Consider scalability and performance of the system
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Round duration - 30 Minutes
Round difficulty - Easy

This is non-tech round.They just want to check your nature ,attitude and team work skills.

Q1. Why do you want to leave your current job and what are your thoughts on the CTC being offered?
Ans. 
I want to leave my current job for better growth opportunities and a more challenging role.
• Seeking new challenges and opportunities for professional growth

• Looking for a role that aligns better with my skills and interests

• Desire to work in a more dynamic and innovative environment

• Seeking better compensation and benefits

• Wanting to expand my knowledge and skills in a different domain
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Round duration - 60 Minutes
Round difficulty - Medium

Timing was around 11 am
Environment was great, it intrigued me to join Blinkit.

Q1. 
Pair Sum Problem Statement
You are given an integer array 'ARR' of size 'N' and an integer 'S'. Your task is to find and return a list of all pairs of elements where each sum of a pair equals 'S'.
Note:
...read more
Ans. 
Find pairs of elements in an array that sum up to a given value, sorted in a specific order.
• Sort the array in non-decreasing order.

• Use two pointers approach to find pairs with sum equal to 'S'.

• Return pairs in sorted order based on first value, with smaller second value coming first.
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Round duration - 60 Minutes
Round difficulty - Medium

Timing 11 am
Interviewer had good knowledge

Q1. Can you explain the activity lifecycle in Android development?
Ans. 
Activity lifecycle in Android development involves various states like onCreate, onStart, onResume, onPause, onStop, onDestroy.
• Activity is created with onCreate() method

• Activity becomes visible with onStart() and onResume() methods

• Activity goes into background with onPause() method

• Activity is stopped with onStop() method

• Activity is destroyed with onDestroy() method
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Q2. Can you explain the fragment lifecycle in Android development?
Ans. 
Fragment lifecycle in Android involves various states like created, started, resumed, paused, stopped, and destroyed.
• Fragments are created using the onCreateView() method.

• Fragments go through states like created, started, resumed, paused, stopped, and destroyed based on user interactions and system events.

• Fragment lifecycle methods include onCreate(), onStart(), onResume(), onPause(), onStop(), and onDestroy().
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Q3. Can you explain the MVVM pattern?
Ans. 
MVVM is a design pattern that separates the user interface from the business logic and data model.
• MVVM stands for Model-View-ViewModel

• Model represents the data and business logic

• View represents the UI components

• ViewModel acts as an intermediary between the Model and View, handling user input and updating the Model

• MVVM promotes separation of concerns and easier unit testing
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Round duration - 30 Minutes
Round difficulty - Easy

This round is cultural fit round