Uber | SDE 2 | Rejected
Summary
I interviewed for an SDE 2 position at Uber and was rejected after several rounds including an OA, phone screen, DSA, LLD, and HLD.
Full Experience
HackerRank OA Questions:
- Given an array of length n, a number k is balanced if there are 2 indices i and j in the array, where arr[i], arr[i+1], ... arr[j] is a permutation of 1, 2, ... k. Return a binary string of length n, where 1 represents if the ith character is balanced. Ex: [4, 1, 3, 2]. Answer: "1011"
- Given an undirected graph rooted at 0 where each node i is represented by a lower case english alphabet. There are m queries. For each query we have a node_from and node_to, figure out if the characters encountered while travelling from node_from to node_to can be used to form a palindrome
Phone Screen DSA Round:
- There are n riders and 1 car with infinite space. Each rider has a range of number of other riders that they are comfortable with. Ex: ith rider is comfortable with 3 to 5 other riders. If this condition is not met they do not ride in the car. Find out the maximum no of riders that is possible to fit in the car
DSA Round:
- https://leetcode.com/problems/find-the-closest-palindrome/
- https://leetcode.com/problems/longest-continuous-subarray-with-absolute-diff-less-than-or-equal-to-limit/description/
LLD Round:
Was given a vague Uber Eats Pricing calculator problem with features like Food items with toppings, size. Other requirements include surge pricing, discounts, BOGO, coupons, and additional discounts for uber one members. I had to discuss with the interviewer to narrow down the requirements and implement it.
HLD Round:
Design a stock price alerting system. The system receives stock prices from an external broker. If the current price of the stock exceeds 5% of the closing price, send a notification. Went into db schema, message queues, at most once notifications and retry mechanisms in case of failures.
For DSA and LLD rounds working code was expected.
Interview Questions (6)
Balanced Subarray Binary String
Given an array of length n, a number k is balanced if there are two indices i and j such that the subarray arr[i], arr[i+1], ..., arr[j] is a permutation of 1, 2, ..., k. Return a binary string of length n where the i‑th character is '1' if the i‑th position is balanced, otherwise '0'. Example: array [4, 1, 3, 2] → output "1011".
Graph Path Palindrome Query
Given an undirected graph rooted at node 0 where each node i is labeled with a lowercase English letter. There are m queries; each query provides a node_from and node_to. Determine whether the characters encountered on the path from node_from to node_to can be rearranged to form a palindrome.
Maximum Riders Fit Problem
There are n riders and one car with infinite capacity. Each rider i is comfortable riding with a number of other riders within a given range [a_i, b_i]. If the number of other riders in the car does not fall within this range, the rider will not join. Find the maximum number of riders that can be placed in the car simultaneously.
Find the Closest Palindrome (LeetCode)
LeetCode problem: given an integer represented as a string, return the nearest palindrome number (excluding the number itself).
Longest Continuous Subarray With Absolute Diff <= Limit (LeetCode)
LeetCode problem: given an array and an integer limit, find the length of the longest continuous subarray such that the absolute difference between any two elements is less than or equal to limit.
Stock Price Alerting System
Design a system that receives real‑time stock prices from an external broker. When the current price of a stock exceeds 5% of its closing price, the system should send a notification. Discuss database schema, message queues, at‑most‑once delivery, and retry mechanisms for failure handling.