Uber backend engineer interviews typically focus on APIs, databases, system design, concurrency, caching, and data structures.
1. Move Through Array
Category: Array coding problem
Move Through Array You are given an array where each element represents the number of steps you can move from that position. Positive numbers move...
Input: ArrayOutput: Computed result
2. OA [CodeSignal] Adventure Levels
Category: Array coding problem
OA [CodeSignal] Adventure Levels You start with initial energy K. You need to clear a series of adventure levels. For each level i: -...
Output: Array
3. OA [CodeSignal] Balanced Numbers in Permutation
Category: Array coding problem
OA [CodeSignal] Balanced Numbers in Permutation Given a permutation p of integers from 1 to n. A number k (where 1 <= k <= n) is called...
Output: Computed result
4. OA [CodeSignal] Count Palindrome Paths in Tree
Category: Tree coding problemGiven a tree with
n nodes where each node has a lowercase English character c[i]. A path is palindromic if the characters along the path can...Input: ListOutput: Computed result
5. OA [CodeSignal] Final Prices After Discount
Category: Array coding problemYou are given an array
prices where prices[i] is the price of an item. For each item at index i, find the first item at index j > i such that...Input: ArrayOutput: Computed result
6. OA [CodeSignal] Jump Game
Category: Array coding problemYou are at position
i in an array. From each position, you can jump to: - i + 1 (one step forward) - Any position i + k where k ends in digit...Input: ArrayOutput: Computed result
7. OA [CodeSignal] Longest Subsequence With Limited Sum
Category: Array coding problemYou are given two arrays:
nums (containing positive integers) and queries (each containing a target sum). For each query, return the maximum...Input: ArrayOutput:** Computed result
8. OA [CodeSignal] Max Throughput With Budget
Category: Algorithm coding problemYou have a pipeline of services. Each service has: - Current throughput
throughput[i] - Cost to scale up by 1 unit scalecost[i] You have a fixed...Input: ListOutput: Integer
9. OA [CodeSignal] Minimum Edge Reversal Root
Category: Graph coding problemGiven a directed graph (represented as a tree with directed edges), choose a root node such that the minimum number of edges must be reversed so that...Input: Graph (nodes and edges)
Output: Integer
10. OA [CodeSignal] Minimum Operation To Reduce n To 0
Category: Algorithm coding problemGiven a positive integer
n, in one operation you may replace n with either: - n = n + 2^i, or - n = n - 2^i for any integer i >= 0. Find...Input: Integer(s)Output: Integer
11. OA [CodeSignal] Purchase Optimization
Category: Array coding problemAlex is shopping at Ozone Gallerie Mall where cubicles are arranged in non-decreasing order of prices from left to right. Given: -
prices: array of...Input: ArrayOutput: Integer
12. OA [CodeSignal] Shortest Good Subarray
Category: Array coding problemGiven an array
arr and an integer k, a subarray is called good if it contains at least k distinct integers. Return the length of the...Input: ArrayOutput: Integer
13. OA [CodeSignal] Touring the Building
Category: Algorithm coding problemYou are on floor 0 of a building and need to reach floor
n. You can use either the lift or stairs. Lift: - Takes t1 time per floor -...Input: Given inputOutput: Computed result
14. Robot Map
Category: Array coding problemGiven a location map and a query, find which robot matches the query. Location Map: A 2D array where each cell contains: -
O = Robot - E =...Input: ArrayOutput: Computed result
15. [Low Level Design] Uber Eats Price Calculation
Category: Algorithm coding problemIn the Uber Eats marketplace, the final price of an order is a dynamic calculation involving multiple factors. Design the core classes and interfaces...Input: Given input
Output: Computed result
16. [Object Oriented Design] Meeting Reservation System
Category: Interval-based coding problem
Meeting Reservation System Design a meeting reservation system that manages meeting rooms and schedules. Implement a MeetingReservationSystem...
Output: Computed result
17. Capital Gains Tax Calculator
Category: String coding problemYou are given a chronologically sorted list of stock transactions. Each transaction is a list of strings in the format `[<timestamp>, <type>,...Input: Array of strings
Output: Computed result
18. Unimodal Cost Function Minimum
Category: Interval-based coding problem
Unimodal Cost Function Minimum You are given a unimodal cost function f(x) = A * (x - C)^2 + D defined over the interval [lo, hi], where `A >...
Output: Computed result
19. Hierarchy Path Finder
Category: Tree coding problem
Hierarchy Path Finder You are given an org chart represented as a tree. Each node in the tree has a unique integer ID and a display name. You are...
Input: ListOutput: Computed result
20. Weight Partition Check
Category: Algorithm coding problem
Weight Partition Check You are given a list of distinct positive integer weights and a capacity value. Determine whether any subset of the weights...
Input: ListOutput: Computed result
21. Straight Line Sequence Search
Category: Grid/matrix coding problem
Straight Line Sequence Search You are given an m x n grid of characters and a target sequence string. Determine whether the sequence appears in...
Output: Computed result
22. Longest Valid Container Nesting
Category: String coding problem
Longest Valid Container Nesting You are given a string consisting only of the characters {, }, [, ], (, ). These represent three levels...
Output: Integer
23. Next Palindrome Number
Category: String coding problem
Next Palindrome Number Given a string num representing a positive integer, find and return the smallest palindrome that is strictly greater than...
Output: Computed result
24. Annotate First Pattern Match
Category: String coding problem
Annotate First Pattern Match You are given a string text containing words separated by spaces, and a list of patterns. For each word in text,...
Output: Computed result
25. Nested Arithmetic Expression Evaluator
Category: String coding problem
Nested Arithmetic Expression Evaluator You are given a string expression containing nested calls to two functions: plus(a, b) and minus(a, b)....
Output: Computed result
26. Process CPU Time Calculator
Category: Interval-based coding problemYou are given a list of log entries from a single-threaded CPU scheduler. Each entry is a list of three strings:
[process_name, action, timestamp],...Input: Array of stringsOutput: Computed result
27. OA [CodeSignal] Prime Jumps
Category: Algorithm coding problem
OA [CodeSignal] Prime Jumps A game is played with the following rules: - A player starts at cell 0 with a score of 0. - There is a row of n cells...
Output: Computed result
28. Palindrome Paths From Query
Category: Tree coding problem
Palindrome Paths From Query A disk stores hierarchical data in an undirected tree with tree_nodes nodes numbered from 0 to tree_nodes - 1,...
Output: Computed result
1. [OA] Longest Increasing Subsequence — optimize delivery times
times, where each element represents the delivery time of a specific order, write a function longestIncreasingSubsequence(times: List[int]) -> int that returns the length of the longest strictly increasing subsequence of delivery times.Example 1:Input:
longestIncreasingSubsequence([10, 22, 9, 33, 21, 50, 41, 60, 80])Output:
6Explanation: The longest increasing subsequence is
[10, 22, 33, 50, 60, 80] with length 6.Example 2:Input:
longestIncreasingSubsequence([3, 10, 2, 1, 20])Output:
3Explanation: The longest increasing subsequence is
[3, 10, 20] with length 3.Constraints:1 <= times.length <= 25001 <= times[i] <= 10^4
2. [OA] Dijkstra's Algorithm — calculate the shortest path for ride-hailing services
G representing the routes between various locations, where each edge has a weight representing the travel time. Implement a function findShortestPath(start: int, end: int) -> List[int], which returns the shortest path between the start and end nodes in terms of the edge weights.start: the starting node (integer)end: the destination node (integer)
Example 1:
Input:
findShortestPath(0, 4)Output:
[0, 2, 3, 4]Explanation: The shortest path from node 0 to node 4 is via nodes 0 -> 2 -> 3 -> 4.Example 2:
Input:
findShortestPath(1, 3)Output:
[1, 3]Explanation: The shortest path from node 1 to node 3 is direct via node 1 -> 3.Constraints:
1 <= number of nodes <= 10^51 <= weight of edges <= 10^3
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