Uber Interview Questions, Process, and Tips

Round duration - 90 minutes
Round difficulty - Medium

There were a total of three questions of 100, 200, and 300 points respectively. Partial points were given if partial tests got passed for any problem. The Codesignal environment was similar to Hackerrank, so not much different. I think the test was held in the afternoon time.

Q1. Kadane's Algorithm
A sub-optimal code was given in the problem. We had to understand what the code does and then write an optimal code which does the same thing. So the code was for finding the maximum sum ...read more
Ans. Brute Force Approach
1. Create a nested loop. The outer loop will go from i = 0 to i = n - k. This will cover the starting indices of all k-subarrays
2. The inner loop will go from j = i to j = i + k - 1. This will cover all the elements of the k-subarray starting from index i
3. Keep track of the maximum element in the inner loop and print it.
Space Complexity: O(1)Explanation:
O(1) because the extra space being used (looping vari...read more
Answered by CodingNinjas
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Q2. Game of stones
Given the count of total stones in a game. Two-player ‘Ale’ and ‘Bob’ are playing the game. Your task is to find who will win the game if both the players are playing optimally.
Rules of t...read more
Ans. Game Theory
• It is clear that if the number of stones is ‘1’ then ‘Ale’ wins the game. If ‘2’ then also ‘Ale’ wins the match, and if ‘3’ then ‘Bob’ wins the game.
• So we can observe that, if anyone has a chance to choose a stone from ‘3’ number of stones then another opponent will the game. If ‘Ale’ choosing the stones from ‘3’ number stone then ‘Bob’ will win and vice versa.
• If the number of stones is ‘4’ then ‘Ale’ will w...read more
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Q3. Return subsets sum to K
Given an integer array 'ARR' of size 'N' and an integer 'K', return all the subsets of 'ARR' which sum to 'K'.
Subset of an array 'ARR&...read more
Ans. Brute Force
Recursively generate all the subsets and keep track of the sum of the elements in the current subset.
Subsets can be generated in the following way. For every element of the array, there are 2 options: 
1. Include the element in the current subset : If we include the element in the current subset, then we decrease the value of ‘K’ by  the value of the element.
2. Do not include the element in the current su...read more
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Round duration - 60 minutes
Round difficulty - Medium

This round was a video call round held on Zoom and the Codesignal platform was to be used for coding the problems. The round started with the interviewer giving a small introduction about him and then asking me to introduce myself.

Q1. Rotting Oranges
You have been given a grid containing some oranges. Each cell of this grid has one of the three integers values:
Value 0 - representing an empty cell.
Value 1 - representing a fresh...read more
Ans. Naïve Solution
The idea is very simple and naive. We will process the rotten oranges second by second. Each second, we rot all the fresh oranges that are adjacent to the already rotten oranges. The time by which there are no rotten oranges left to process will be our minimum time.
 
In the first traversal of the grid, we will process all the cells with value 2 (rotten oranges). We will also mark their adjacent cells ...read more
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Q2. Find Indices For Local Minimas and Maximas
Given an array “arr” of “N” integers. Your task is to find and return all the indices of local minima and local maxima in the given array. You need to return the ...read more
Ans. Brute Force
The idea is to iterate through the given array and at each index i, we check its neighbors to check if it's local minima or maxima.
 
Steps:
 
• We create two lists namely minima and maxima, to store all the indices of local minima and local maxima respectively.
• First, we check for the local maxima and minima conditions for the first element.
• Then we iterate through the given array from index 1 to N - 2, a...read more
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Round duration - 60 minutes
Round difficulty - Medium

The setup was exactly similar to the first interview round. The interviewer was very friendly. My advice will be to see the interviewer as a team mate and think you have to solve the question together with him. Don't panic and start speaking out what observations you can make about the problem.

Q1. Sort by Kth bit
You are given an array/list ‘ARR’ of ‘N’ positive integers and an integer ‘K’. Your task is to group all the array elements with ‘K-th’ bit (rightmost bit is ‘1st’ bit) equal to 0 followed ...read more
Ans. Iteration
The idea is to simply iterate through the ‘ARR’ and check each element whether its ‘K-th’ bit is 0 or 1, and add the element to the respective group.
 
Here is the algorithm:
 
1. Create an array/list ‘TEMP_ARR’ of size = ‘N’ for storing all the elements whose ‘K-th’ bit is 1.
2. Initialize a variable ‘j’ = 0 to iterate through ‘TEMP_ARR’.
3. Initialize a variable ‘p’ = 0 to iterate through ‘ARR’.
4. Run a loop from 0 ...read more
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Round duration - 60 minutes
Round difficulty - Medium

It was already night time till this interview started because all the three interview rounds were held on the same day. This was not a DS+Algorithms round. He first asked me to introduce myself. So I started by telling what all I have done in my college up till now and then I told him about my internship experience at myKaarma which just ended few days back. There was around 10-15 minutes discussion on what I was working on in my intern project.

Q1. System Design
This was not exactly a system design question but he asked me how can I design a platform which can be used by political parties to do online campaigning. It was a very open ended question. Ac...read more
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Round duration - 90 Minutes
Round difficulty - Medium

it was time bound coding test round. The questions were from array and string. There were 2 questions.

Q1. K-Palindrome
You are given a string ‘str’. You need to find out whether the string is a K-Palindrome or not.
A string is called a K-Palindrome if, after removing at most ‘k’ characters from the string, i...read more
Ans. 
I had done before the coding test so I solved in same way by splitting whole staring in three parts (start+mid+end).
Answered by CodingNinjas
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Round duration - 30 Minutes
Round difficulty - Easy

in this round manager spoke to me and explained about project and joining date later hr spoke to me regarding on boarding process

Q1. Basic HR questions
Introduce Yourself.
Your Expectations from the company.
Past experiences.
Ans. 
Tip 1 : Be confident. That's it.
Answered by CodingNinjas
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