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CodeSignal OAs SRE Coding Questions

56 practice questions for CodeSignal OAs SRE interviews

CodeSignal OAs SRE interviews focus on reliability engineering, incident management, capacity planning, monitoring, and balancing system stability with feature velocity.

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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 Verified Question #4

4. OA[CodeSignal] Employee Management System


Category: Graph coding problem
You 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 Medium Verified Question #5

5. OA[CodeSignal] Find Effective Communication Channels


Category: String coding problem
You are given billing records, communication logs, and payment records for a healthcare system. Your task is to determine which communication channel...
Input: String
Output: Computed result
coding Hard Verified Question #6

6. 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: -...
Input: Array
Output: Array
coding Hard Verified Question #7

7. 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...
Input: Array
Output: Computed result
coding Hard Verified Question #8

8. OA [CodeSignal] Count Palindrome Paths in Tree


Category: Tree coding problem
Given 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: List
Output: Computed result
coding Medium Verified Question #9

9. OA [CodeSignal] Final Prices After Discount


Category: Array coding problem
You 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: Array
Output: Computed result
coding Medium Verified Question #10

10. OA [CodeSignal] Jump Game


Category: Array coding problem
You 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: Array
Output: Computed result
coding Medium Verified Question #11

11. OA [CodeSignal] Longest Subsequence With Limited Sum


Category: Array coding problem
You are given two arrays: nums (containing positive integers) and queries (each containing a target sum). For each query, return the maximum...
Input: Array
Output:** Computed result
coding Hard Verified Question #12

12. OA [CodeSignal] Max Throughput With Budget


Category: Algorithm coding problem
You 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: List
Output: Integer
coding Hard Verified Question #13

13. OA [CodeSignal] Minimum Edge Reversal Root


Category: Graph coding problem
Given 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 Medium Verified Question #14

14. OA [CodeSignal] Minimum Operation To Reduce n To 0


Category: Algorithm coding problem
Given 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
coding Hard Verified Question #15

15. OA [CodeSignal] Purchase Optimization


Category: Array coding problem
Alex 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: Array
Output: Integer
coding Medium Verified Question #16

16. OA [CodeSignal] Shortest Good Subarray


Category: Array coding problem
Given 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: Array
Output: Integer
coding Hard Verified Question #17

17. OA [CodeSignal] Touring the Building


Category: Algorithm coding problem
You 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 input
Output: Computed result
coding Medium Verified Question #18

18. [CodeSignal] Maximum Zero-Sum Triplets


Category: Array coding problem
# Question You are given an array A of integers. A triplet is a sequence of three consecutive elements. A triplet is called zero-sum if the...
Input: Array
Output: Computed result
coding Easy Verified Question #19

19. [CodeSignal] Coin Table Game


Category: String coding problem
# Question A player is playing a game in which coins are placed on and removed from a table. The game consists of multiple rounds. At the beginning...
Input: String
Output: Computed result
coding Easy Verified Question #20

20. [CodeSignal] Count Non-Dominant Elements


Category: Array coding problem
# Question Given an array of integers numbers, count all elements that are not equal to numbers[0] or numbers[1] (if those indices exist in the...
Input: Array of integers
Output: Computed result
coding Easy Verified Question #21

21. [CodeSignal] Sort Words By Vowel Consonant Difference


Category: Array coding problem
# Question You are given a string text consisting of unique lowercase English words separated by spaces. For each word, compute the absolute...
Input: Array
Output:** Computed result
coding Medium Verified Question #22

22. [CodeSignal] Warehouse Robot Commands


Category: Matrix coding problem
# Question In a highly automated warehouse, a robot organizes packages stored in a rectangular grid. The grid is represented as a 2D list of integers...
Input: Matrix (2D array)
Output: Computed result
coding Hard Verified Question #23

23. [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 integers
Output: Array
coding Hard Verified Question #24

24. [CodeSignal] Warehouse Emergency Deliveries


Category: Array coding problem
Amazon has opened a new warehouse recently. There are no products in the warehouse currently. The warehouse is under inspection for n days. The...
Input: Array
Output: Integer
coding Hard Verified Question #25

25. [CodeSignal] Permutation Sorter


Category: Combinatorics coding problem
Amazon 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 #26

26. [CodeSignal] Maximum Product Rating


Category: Array coding problem
The 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: Array
Output: Computed result
coding Medium Verified Question #27

27. [CodeSignal] Drone Hub Travel


Category: Array coding problem
Amazon is expanding its next-generation drone delivery network, consisting of m hubs arranged in a circular ring (Hub 1 is adjacent to Hub m)....
Input: Array
Output: Computed result
coding Medium Verified Question #28

28. [CodeSignal] Minimum Security Groups


Category: Array coding problem
A financial services company has requested AWS for a private deployment of its cloud network. There are n servers in the network where the security...
Input: Array
Output: Integer
coding Medium Verified Question #29

29. [CodeSignal] Maximum Secure Deliveries


Category: Array coding problem
You are given an array deliveryLogs of size n, where each element represents the number of parts delivered in the i-th log. You are also given...
Input: Array
Output: Integer
coding Medium Verified Question #30

30. Service Log Aggregator


Category: Trie-based coding problem
A distributed system emits log entries from multiple services and worker threads. Each log entry is a colon-separated string in the format...
Input: Array
Output: Computed result

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