Online coding assessments (OAs) are the first technical filter for most companies. Performing well here determines whether you reach the interview stage.
Platform Used By Format Time Limit
HackerRank Goldman Sachs, Cisco, Dell 2-4 coding problems 60-120 min CodeSignal Meta, Uber, Zoom 2-4 problems (GCA/general) 70-120 min LeetCode Various (via hiring modules) 1-4 problems Varies Codility Samsung, HP, Cerner 2-3 problems 60-90 min HackerEarth Indian startups, service companies 2-4 problems 60-120 min
Category Frequency Examples
Arrays/Strings Very High Two pointers, sliding window, subarrays Hash Maps Very High Frequency counting, anagrams, complements Trees/Graphs High Traversals, BFS/DFS, LCA Dynamic Programming Medium Knapsack variants, LCS, edit distance Math/Logic Medium Number theory, bit manipulation SQL (for data roles) Medium Joins, aggregations, window functions
Verify the allowed languages and IDE restrictions.
Practice on the specific platform to learn its interface.
Prepare a local template with common imports and utility functions.
Read all problems first and solve the easiest to secure partial points.Start with brute force , then optimize. Partial credit is common.Test edge cases — empty input, single element, duplicates, negative numbers.Manage time — spend no more than 25 minutes per problem before moving on.
Problem Suggested Time Target
Easiest 15 min Full solution Easy-Medium 20 min Full solution Medium 25 min Optimize or partial Hard 30 min Brute force or partial
Companies employ several measures to ensure fairness:
Measure Description
Tab/window monitoring Detects switching tabs or applications Copy-paste detection Flags pasted code from external sources Webcam proctoring Records video during the assessment Question variation Each candidate gets slightly different problems Plagiarism detection Compares submissions across candidates
Week Focus Problems
1 Arrays, strings, hash maps 30 2 Linked lists, stacks, queues 20 3 Trees, BST, graphs BFS/DFS 25 4 Dynamic programming basics 20 5 Mock assessments on platform 3-4 full tests
Don’t panic if you can’t solve the hardest problem — most candidates can’t.
Write clean, readable code; automated reviews penalize messy submissions.
If stuck, implement brute force and move on — partial credit adds up.
Practice typing speed; slow typing costs points on timed assessments.