Placement Prep · Infosys
Infosys coding round prep: SE, DSE and SP roles
Infosys hires freshers into several bands, from Systems Engineer to the higher-paying Digital Specialist Engineer and Specialist Programmer roles. The higher the band, the more the coding round decides it. This guide explains what those rounds typically test, which data structures and algorithms come up most, and gives you a 4-week plan with a free lab for each topic.
Free interactive DSA labs · runs in your browser · no install
How Infosys fresher hiring typically works
Infosys has used several routes over the years, including the InfyTQ platform, the HackWithInfy contest and regular on-campus and off-campus drives. Names, eligibility and formats change, so treat this as a general picture and confirm the details in the official notice.
- Systems Engineer (SE)-style tests typically mix aptitude, logical reasoning, verbal ability and pseudocode or code-output questions.
- DSE and SP-style coding rounds typically give you a few problems of rising difficulty, often roughly one easy, one medium and one hard, in a fixed time window.
- Shortlisted candidates usually go on to a technical interview where you explain your approach, discuss complexity and sometimes code live.
Topics that matter most, mapped to labs
| Topic | Why it shows up | Practise it |
|---|---|---|
| Dynamic programming | The most common shape for the hardest problem: count ways, minimise cost, pick a best subset | Coin change, Knapsack, DP table |
| Graphs | Connectivity, shortest paths, ordering with dependencies | BFS/DFS, Dijkstra, Topo sort, Union-Find |
| Greedy + sorting | Intervals, scheduling, choose-the-best-next problems | Merge intervals, Heap |
| Binary search | On a sorted array, and on the answer itself (minimum capacity, maximum distance) | Binary search |
| Backtracking | Generate all subsets, permutations, valid placements | N-Queens, Backtracking |
| Arrays & strings | The easy problem, and a building block of the others | Hashing, Sliding window, Kadane |
Pseudocode and output questions
For SE-style tests, expect short snippets where you trace loops, recursion and bitwise operations by hand. Practise by predicting the result before you run anything. Every BitBootcamp lab starts with exactly that: you commit to a prediction, then watch the real behaviour.
The 4-week Infosys plan
Aimed at the DSE/SP coding round. If you are targeting the SE band only, spend weeks 3 and 4 on aptitude and pseudocode instead of hard DP.
| Week | Focus | Daily target | Labs |
|---|---|---|---|
| Week 1 | Core patterns: hashing, two pointers, sliding window, sorting | 3 easy + 1 medium problem | Hashing, Sliding window, Quicksort |
| Week 2 | Recursion, backtracking, binary search on the answer | 2 medium problems, one written from memory the next day | Recursion, N-Queens, Binary search |
| Week 3 | Dynamic programming: 1-D, then 2-D tables, then knapsack-style | 2 DP problems; draw the table before coding | Coin change, DP table, Knapsack |
| Week 4 | Graphs, plus two timed 3-problem mocks | 1 graph problem + 1 full mock every other day | BFS/DFS, Dijkstra, Union-Find |
Practise this now
Start with the topics that decide the hard problem. Each lab lets you change the input and watch the algorithm respond, so the pattern sticks.
Coin Change (DP)
Your first DP table: watch dp[] fill left to right, and see why greedy overpays and plain recursion explodes.
0/1 Knapsack
Take it or leave it: the DP that underlies a whole family of subset and budget questions.
DP Table Builder
LCS and edit distance: watch a 2-D table fill cell by cell from smaller sub-problems.
Graph Search: BFS vs DFS
BFS floods outward in rings and finds the shortest path; DFS dives deep. The queue-vs-stack difference.
Dijkstra's Shortest Path
Settle the nearest node, relax its edges, repeat with a priority queue, on a real weighted graph.
Union-Find (DSU)
Are two things connected? Merge sets as edges stream in and catch a redundant edge as a cycle.
Binary Search
Halve a sorted array every step, plus the two off-by-one bugs that cost marks under time pressure.
N-Queens & Backtracking
Choose, explore, un-choose. The skeleton behind permutations, subsets, sudoku and word search.
In the technical interview
- Explain before you code. State the brute force, its complexity, then how you will improve it.
- Know your own submission. Interviewers often ask you to walk through the code you wrote in the online round.
- Revise CS basics: OOP concepts, a little DBMS and SQL, and operating-system fundamentals often come up. Our free SQL course and SQL joins lab cover the database side.
Frequently asked questions
What is the difference between Infosys SE, DSE and SP roles?
They are different fresher bands. Systems Engineer is the entry band; Digital Specialist Engineer and Specialist Programmer are higher bands with higher pay that typically require a stronger performance in a harder coding round. Exact names and packages change, so check the current notice.
What topics come up in the Infosys SP and DSE coding round?
The harder problems typically need dynamic programming, graph algorithms, greedy with sorting or binary search on the answer. The easier problem is usually arrays or strings. Practising those core techniques is the most reliable preparation.
How many questions are in the Infosys coding round?
It has typically been a small set of problems of increasing difficulty, often three, in a fixed time limit. The number and time can change between drives, so confirm in the official instructions for your test.
How should I prepare for Infosys pseudocode questions?
Trace short snippets by hand: loops, nested loops, recursion and bitwise operators. Write down variable values line by line. Predict first, then check. Speed comes from doing many small ones rather than a few long ones.
Is dynamic programming really necessary for Infosys?
For the SE band, usually not. For DSE and SP, DP is one of the most common shapes for the hardest problem, so it is worth at least a full week of focused practice.
Aiming for DSE or SP? Check where you stand.
The 2-minute readiness check shows which DSA topics are solid and which need a week of work.
All prep guides TCS NQT Wipro · Accenture · Cognizant Amazon SDE DSA in Hindi
BitBootcamp is an independent learning platform and is not affiliated with, endorsed by, or partnered with any company named on this page. Company names are used only to describe the recruitment drives students prepare for. Exam patterns change between seasons, so always confirm the current format in the official notice for your drive.