CodeSignal OAs software engineer interviews cover algorithms, data structures, system design, and coding problems drawn from real interview rounds.
Software Engineer
Backend Engineer
Frontend Engineer
Full Stack Engineer
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Engineering Manager
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UX/UI Designer
QA Engineer
coding
Hard
Verified Question
#1
1. OA[CodeSignal] Cloud File Storage System
Category: Graph coding problem
Question Your task is to implement a simple in-memory cloud storage system that maps objects (files) to their metadata (name, size, etc.). You...
Input: Graph (nodes and edges)Output: Array
coding
Hard
Verified Question
#2
2. OA[CodeSignal] Design Banking System
Category: Graph coding problem
Question Design a banking system that supports account management, transactions, and various financial operations.
Input: Graph (nodes and edges)Output: Computed result
coding
Hard
Verified Question
#3
3. OA[CodeSignal] In-Memory Database
Category: Graph coding problem
Description Implement a simplified in-memory database that supports record manipulation with various operations. The system should handle basic...
Input: Graph (nodes and edges)Output: Array
coding
Hard
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#4
4. OA[CodeSignal] Employee Management System
Category: Graph coding problemYou are tasked with designing an employee management system that tracks work sessions, calculates work hours, handles promotions, and manages salary...Input: Graph (nodes and edges)
Output: Computed result
coding
Hard
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#5
5. 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
coding
Hard
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#6
6. 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
coding
Hard
Verified Question
#7
7. 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
coding
Hard
Verified Question
#8
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
coding
Hard
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#9
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
coding
Hard
Verified Question
#10
10. 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
coding
Hard
Verified Question
#11
11. 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
coding
Hard
Verified Question
#12
12. [CodeSignal] House Segments After Destruction
Category: Array coding problem
Question You are monitoring the building density in a district of houses. The district is represented as a number line, where each house is located...
Input: Array of integersOutput: Array
coding
Hard
Verified Question
#13
13. [CodeSignal] Warehouse Emergency Deliveries
Category: Array coding problemAmazon has opened a new warehouse recently. There are no products in the warehouse currently. The warehouse is under inspection for
n days. The...Input: ArrayOutput: Integer
coding
Hard
Verified Question
#14
14. [CodeSignal] Permutation Sorter
Category: Combinatorics coding problemAmazon engineers are testing a new tool, the Permutation Sorter, built to reorder sequences using limited operations. Given a permutation of...Input: Integer(s)
Output: Integer
coding
Hard
Verified Question
#15
15. [CodeSignal] Maximum Product Rating
Category: Array coding problemThe engineers at Amazon are working on a new rating system for their products. For each product, an array
customer_rating is maintained for the...Input: ArrayOutput: Computed result
coding
Hard
Verified Question
#16
16. OA [CodeSignal] Knowledge Base System
Category: Graph coding problemDesign and implement a personal knowledge base called
KnowledgeBaseSystem that stores articles with CRUD operations. The system operates entirely...Input: Graph (nodes and edges)Output: Computed result
coding
Hard
Verified Question
#17
17. [CodeSignal] Synchronized Pipeline Delays
Category: Binary tree coding problemA hierarchical data pipeline consists of
n broadcast stages, numbered 1 to n, arranged in a perfect binary tree rooted at stage 0. Each stage...Input: Binary treeOutput: Computed result
coding
Hard
Verified Question
#18
18. [CodeSignal] Fibonacci Storage System
Category: Graph coding problemA research facility stores artifacts in underground vaults. Each vault has multiple tiers, indexed from 0 (deepest) upward. The capacity of each tier...Input: Graph (nodes and edges)
Output: Computed result
coding
Hard
Verified Question
#19
19. [CodeSignal] Fixed Price Purchase Optimizer
Category: Algorithm coding problemA procurement team must purchase n identical components one at a time. For each component, the quoted market price is drawn independently and...Input: Given input
Output: Integer
coding
Hard
Verified Question
#20
20. [CodeSignal] Battery Rotation Scheduler
Category: Array coding problemA remote system uses a circular array of backup generators to sustain a critical task. Each generator can power the system for a fixed number of...Input: Array
Output: Integer
coding
Hard
Verified Question
#21
21. [CodeSignal] Grid Arithmetic Path
Category: Matrix coding problemYou are given a grid where each cell contains either a single digit ('0' to '9') or an arithmetic operator ('+' or '-'). Starting from any cell, you...Input: Matrix (2D array)
Output: Integer
coding
Hard
Verified Question
#22
22. [CodeSignal] Round-Robin Package Dispatcher
Category: Trie-based coding problemA logistics platform assigns packages to processing stations in round-robin order. You are given stationCapacity (max packages each station can...Input: Given input
Output: Integer
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