Coding questions
BARC Online Assessment
Overview
Here is how public prep guides and student write-ups describe the BARC online assessment. This is not an official company brochure.
DAE Scientific Officer path via CBT/GATE screen + heavy technical interview - not a private IT OA.
Usual selection rounds
Rounds students usually mention: Online screening exam OR valid GATE score → Personal interview
| Item | From student reports |
|---|---|
| Platform | BARC online screening CBT (multi-city) or GATE screen |
| Online test summary | Discipline-specific online exam; CS syllabus spans DSA, COA, OS, DBMS, CN, theory, etc. No TA for exam travel noted in GFG summary. Final weight is mostly interviews after a short screen after screen. |
| Eligibility notes | As per OCES/DGFS notification |
| Branches (reported) | Engineering/science disciplines listed in ad (incl. CS code 26) |
Online test sections
| Section | Questions | Time | Notes |
|---|---|---|---|
| Discipline MCQs | Screening paper (commonly cited as 100 Q style across years - confirm current notification) | - | GATE path can skip CBT screen |
Extra notes from sources
- Always download current BARC OCES/DGFS PDF.
Sample practice question styles
These are practice questions for speed - not claimed to be from a real BARC live paper.
Coding Q1: Move zeros
Problem: Move all zeros in an array to the end while keeping the relative order of non-zero elements.
Approach: Two pointers: write non-zeros toward the front, then fill the remainder with zeros. Or swap zeros as you scan.
Complexity: O(n) time, O(1) space
BARC tip: Restate the problem, sketch a brute-force idea, then tighten it. Call out edge cases (empty input, single element, overflow) before you write code.
Coding Q2: Rotate array
Problem: Rotate an array to the right by k steps. Example: [1,2,3,4,5,6,7], k = 3 → [5,6,7,1,2,3,4].
Approach: Normalize k %= n. Reverse the whole array, reverse the first k elements, then reverse the rest. That yields the rotation in place.
Complexity: O(n) time, O(1) space
BARC tip: Restate the problem, sketch a brute-force idea, then tighten it. Call out edge cases (empty input, single element, overflow) before you write code.
Coding Q3: First unique character
Problem: Find the first non-repeating character in a string and return its index, or -1 if none exists.
Approach: Count frequencies in one pass (hash map or array of 26 for lowercase). Second pass returns the first index with count 1.
Complexity: O(n) time
BARC tip: Restate the problem, sketch a brute-force idea, then tighten it. Call out edge cases (empty input, single element, overflow) before you write code.
Coding Q4: Stack with min
Problem: Design a stack that supports push, pop, top, and getMin in average O(1) time.
Approach: Keep a parallel min-stack (or store pairs). When pushing, also push the new minimum. When popping, pop both stacks.
Complexity: O(1) per operation amortized
BARC tip: Restate the problem, sketch a brute-force idea, then tighten it. Call out edge cases (empty input, single element, overflow) before you write code.
Prep tips from those student reports
- GATE-level discipline depth
- Interview fundamentals over aptitude tricks
- Read official notification
Sources
These notes come from public reports and can differ by campus, year, and role. If your college placement email or the official careers/notification PDF says something different, follow that.